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WO2023059181A1 - Polymer latex for the preparation of an elastomeric film having microbial resistance - Google Patents

Polymer latex for the preparation of an elastomeric film having microbial resistance Download PDF

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Publication number
WO2023059181A1
WO2023059181A1 PCT/MY2022/050091 MY2022050091W WO2023059181A1 WO 2023059181 A1 WO2023059181 A1 WO 2023059181A1 MY 2022050091 W MY2022050091 W MY 2022050091W WO 2023059181 A1 WO2023059181 A1 WO 2023059181A1
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Prior art keywords
ethylenically unsaturated
acid
monomers
meth
polymer latex
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PCT/MY2022/050091
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French (fr)
Inventor
Mun Hwa CHONG
Zhenli Wei
Yi-Fan GOH
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Synthomer Sdn Bhd
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Synthomer Sdn Bhd
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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/18—Manufacture of films or sheets
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2300/00—Characterised by the use of unspecified polymers
    • C08J2300/26—Elastomers
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2309/00—Characterised by the use of homopolymers or copolymers of conjugated diene hydrocarbons
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2309/00—Characterised by the use of homopolymers or copolymers of conjugated diene hydrocarbons
    • C08J2309/02—Copolymers with acrylonitrile

Definitions

  • the present invention relates to a polymer latex for the preparation of an elastomeric film, to such elastomeric films and articles comprising said elastomeric films, to latex compositions comprising said polymer latex and to methods for making articles using said film, e.g., dip-molded articles.
  • Medical gloves are used during medical examination and procedures that help prevent the spread of infections. Medical gloves are used to prevent the transfer of infection between the medical workers and their patients. It is important that medical gloves are sterile, i.e., are free of microbiological contamination including bacteria, fungi and yeast. Sterile gloves are required for all surgical procedures and other medical purposes involving greater risk and danger of infection. Sterile examination gloves are available in individual packages, but the gloves remain sterile only until the package is opened, after which they can carry infections. In addition, bio-microbial infection of the polymer latex composition during production of the medical gloves may occur, resulting in microbial-infected medical gloves. Typically, biocides are used to prevent microbial infection of the polymer latex composition and the gloves.
  • WO 2017/148957 A1 relates to medical examination gloves comprising natural or nitrile rubber latex, and a water-soluble singlet oxygen generator.
  • Another object is to provide a polymer latex composition suitable for producing medical gloves such as examination and/or surgical gloves.
  • Surgical gloves must have good stress retention properties and superior softness. Poor stress retention leads to poor fitting of the glove to the forearm part of a surgeon resulting possibly in cross-contamination.
  • another object of the present invention is to provide a polymer latex that gives elastomeric films that have excellent stress retention properties and superior softness and such polymer latex can be used in a range of articles but in particular they are suitable for use in surgical glove as well as condom applications.
  • natural latex surgical gloves are employed. But natural rubber may cause protein allergy issues.
  • Other polymers such as polyisoprene or polychloroprene are also used for making surgical gloves.
  • the processing costs for these materials are very high and the production is not environmental-friendly. Therefore, another object of the present invention, is to provide a polymer latex composition, which is allergy and environmentally-friendly.
  • the present invention relates to a polymer latex composition for the preparation of an elastomeric film comprising a polymer latex obtainable by free-radical emulsion polymerization of a mixture of ethylenically unsaturated monomers comprising: (a) 15 to 99 wt.-% of conjugated dienes; (b) 0 to 80 wt.-% of ethylenically unsaturated nitrile monomers; (c) 0 to 70 wt.-% of vinyl aromatic monomers; the sum of ethylenically unsaturated nitrile monomers (b) and vinyl aromatic monomers (c) being 0.95 to 84.95 wt.- %; (d) 2.5 to 10.0 wt.-% of an ethylenically unsaturated acid comprising an acid functional group, and a spacer group separating the ethylenically unsaturated group and the acid functional group by at least 4 atoms; and (a) 15 to 99
  • the acid functional group of the ethylenically unsaturated acid (d) may be selected from carboxylic acid groups and phosphorous containing acid groups, preferably carboxylic acid groups.
  • the ethylenically unsaturated acid (d) may be selected from compounds having the structure:
  • CHR 2 CR 1 - A - X, wherein R 1 is selected from H and C1-C4 alkyl; R 2 is selected from H or - A - X; A is a divalent spacer group separating the ethylenically unsaturated group and the functional group X by at least 4 atoms independently at each occurrence selected from: - (C(O) - W)n- Y - (O)m-; - (C(O) - W) n - Y - O- C(O) - Y - and
  • n, m, k and p are integers independently at each occurrence selected from 0 or 1 ; W is - O - or - NR 3 -; R 3 is selected from H and C1-C4 alkyl; Y is independently at each occurrence selected from optionally substituted linear, branched, cyclic or aromatic C 2 to C 3 o divalent hydrocarbon or hetero hydrocarbon groups; X is selected from - C(O)OH and - P(O)(OH) 2 ; with the proviso that if X is - C(O)OH m is 0; or- A - X is selected from - C(O) - O - (Y -C(O) - O)i - H, wherein I is an integer from 2 to 10, preferably from 2 to 7; and mixtures thereof.
  • the ethylenically unsaturated acid (d) may be present from 3.0 to 8.5 wt.-%, preferably from 3.4 to 8.0 wt.-%, more preferably from 3.6 to 7.0 wt.-%, even more preferably 3.6 to 6.5 wt.-%, most preferably from 3.6 to 6.0 wt.-%, based on the total weight of the ethylenically unsaturated monomers in the monomer mixture.
  • the mixture of ethylenically unsaturated monomers for the preparation of an elastomeric film comprising a polymer latex obtainable by free-radical emulsion polymerization may further comprise (f) up to 10.0 wt.-%, preferably in a range of from 0 to 7.0 wt.-%, more preferably in a range of 0 to 3.5 wt.-% of an ethylenically unsaturated acid being different from (d), based on the total weight of the ethylenically unsaturated monomers in the monomer mixture.
  • the ethylenically unsaturated acid (d) and the ethylenically unsaturated acid (f) may be present in an amount in the range of up to 10.0 wt.-%, preferably in the range of up to 8.0 wt.-%, more preferably in a range of up to 6.0 wt.-%, based on the total weight of the ethylenically unsaturated monomers in the monomer mixture.
  • the ethylenically unsaturated acid (f) may be selected from
  • carboxylic acids and salts thereof preferably selected from (meth)acrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, and salts thereof;
  • - ethylenically unsaturated polycarboxylic acid anhydride preferably selected from maleic anhydride, methacrylic anhydride, cis-cyclohexene-1 ,2-dicarboxylic anhydride, and dimethylmaleic anhydride, bromomaleic anhydride, 2,3-dichloromaleic anhydride, citraconic anhydride, crotonic anhydride, itaconic anhydride, (2-dodecen-1 -yl) succinic anhydride;
  • polycarboxylic acid partial ester monomers and salts thereof preferably selected from monomethyl maleate, monomethyl fumarate, monoethyl maleate, monoethyl fumarate, monopropyl maleate, monopropyl fumarate, monobutyl maleate, monobutyl fumarate, mono(2-ethyl hexyl) maleate, mono(2-ethyl hexyl) fumarate; and combinations thereof.
  • the conjugated dienes are selected from butadiene, isoprene, 2,3-dimethyl-1 ,3- butadiene, 2-ethyl-1 ,3-butadiene, 1 ,3-pentadiene, myrcene, ocimene, farnasene and combinations thereof;
  • the ethylenically unsaturated nitrile monomers are selected from (meth)acrylonitrile, alpha-cyanoethyl acrylonitrile, fumaronitrile, alpha-chloronitrile and combinations thereof;
  • the vinyl aromatic monomers are selected from styrene, alpha-methyl styrene, vinyl toluene and combinations thereof;
  • the co-polymerizable ethylenically unsaturated compounds are selected from (e1 ) alkyl esters of ethylenically unsaturated acids, preferably selected from methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, iso-propyl (meth)acylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate and combinations thereof;
  • (e3) amides of ethylenically unsaturated acids preferably selected from (meth)acryl amide N-methylol amide groups and combinations thereof;
  • alkoxyalkyl esters of ethylenically unsaturated acids preferably selected from ethoxyethyl acrylate, methoxyethyl acrylate and combinations thereof;
  • (e6) monomers having at least two ethylenically unsaturated groups preferably selected from divinyl benzene, ethylene glycol dimethacrylate, 1 ,4 butanediol di(meth)acrylate and combinations thereof;
  • the mixture of ethylenically unsaturated monomers for the polymer latex may comprise:
  • conjugated dienes preferably selected from butadiene, isoprene and combinations thereof, more preferred butadiene;
  • the polymer latex composition may be completely free of a biocide.
  • the pH of the polymer latex composition may be in the range of 6.0 to less than 7.5, preferably of 6.5 to 7.2.
  • the polymer latex composition may further comprise an oxirane functional compound.
  • the invention relates to a method for preparing a polymer latex composition
  • preparing a polymer latex by free-radical emulsion polymerization of a mixture of ethylenically unsaturated monomers comprising:
  • Another aspect of the present invention relates to use of the polymer latex composition as discussed or obtained by the method as discussed for the production of dip-molded articles or for coating or impregnating a substrate, preferably a textile or ceramic substrate.
  • the invention relates to a compounded latex composition suitable for the production of dip-molded articles comprising the polymer latex composition as discussed or obtained by the method as discussed, and optionally adjuvants selected from sulfur vulcanization agents, accelerators for sulfur vulcanization, crosslinkers, polyvalent cations and combinations thereof.
  • the monomer mixture to obtain the polymer latex for the compounded polymer latex composition may further comprise an ethylenically unsaturated acid (f).
  • the compounded latex composition may comprise 0 to 2.8 wt.-%, preferably 0.5 to 2.8 wt.- %, more preferred 1 .0 to 2.0 wt.-%, most preferred 1 .5 to 2.0 wt.-% sulfur and 0 to 2.8 wt.- %, preferably 1 .0 to 2.0 wt.-%, more preferred 1 .2 to 1 .8 wt.-% of sulfur vulcanization agents and 0.5 wt.-% to 2.5 wt.-% of ZnO, the weight percentages being based on solid latex polymer.
  • Another aspect of the present invention relates to a method for making dip-molded articles by a) providing a compounded latex composition as described; b) immersing a mold having the desired shape of the final article in a coagulant bath comprising a solution of a metal salt; c) removing the mold from the coagulant bath and optionally drying the mold; d) immersing the mold as treated in step b) and c) in the compounded latex composition of step a); e) coagulating a latex film on the surface of the mold; f) removing the latex-coated mold from the compounded latex composition and optionally immersing the latex-coated mold in a water bath; g) optionally drying the latex-coated mold; h) heat treating the latex-coated mold obtained from step e) or f) at a temperature of 40°C to 180°C, preferably 70°C to 120°C; and
  • the compounded latex composition may be matured for at least 3 hrs, preferably from 24 to 48 hrs.
  • another aspect of the present invention relates to an elastomeric film made from the polymer latex composition as described or obtained by the method for preparing a polymer latex composition as described or the compounded latex composition as described.
  • Another aspect of the present invention relates to an article comprising the elastomeric film as described.
  • the article may be selected from surgical gloves, examination gloves, condoms, catheters, industrial gloves, textile-supported gloves and household gloves, preferably surgical gloves.
  • a further aspect of the present invention relates to a method for repairing an elastomeric film as described or an article as described by a) providing elastomeric film as described that is damaged or an article as described comprising a damaged elastomeric film, the damaged elastomeric film having at least surfaces to be reconnected; b) re-joining the surfaces of the damaged film; c) heating or annealing the damaged elastomeric film while maintaining intimate contact of the rejoined surfaces of the damaged film at a temperature of 40°C to 200°C.
  • Another aspect of the present invention relates to a method for recycling an elastomeric film as described or an article as described comprising an elastomeric film by cutting, shredding or comminuting said elastomeric film or article to form particles of the elastomer, optionally blending the obtained particles with particles of virgin elastomer, and forming a recycled film or article by subjecting the particles to a pressure of 1 - 20 MPa and a temperature of 40°C to 200°C.
  • the invention relates to use of a polymer latex obtained by free-radical emulsion polymerization of a mixture of ethylenically unsaturated monomers comprising at least 2.5 wt.% of an ethylenically unsaturated acid, the weight percentage being based on the total weight of the ethylenically unsaturated monomers in the monomer mixture, wherein the ethylenically unsaturated acid comprises an acid functional group; and a spacer group separating the ethylenically unsaturated group and the acid functional group by at least 4 atoms; for providing microbial resistance in a polymer latex composition for the preparation of an elastomeric film and/or in an elastomeric film made from the polymer latex composition.
  • Another aspect of the present invention relates to use of at least 2.5 wt.% of an ethylenically unsaturated acid in a mixture of ethylenically unsaturated monomers in the preparation of a polymer latex by free-radical emulsion polymerization of a mixture of ethylenically unsaturated monomers, the weight percentage being based on the total weight of the ethylenically unsaturated monomers in the monomer mixture; wherein the ethylenically unsaturated acid comprises an acid functional group; and a spacer group separating the ethylenically unsaturated group and the acid functional group by at least 4 atoms; for providing microbial resistance in a polymer latex composition for the preparation of an elastomeric film and/or in an elastomeric film made from the polymer latex composition.
  • the polymer latex composition according to one aspect of the present invention for the preparation of an elastomeric film comprises a polymer latex, which is obtainable by free- radical emulsion polymerization of a mixture of ethylenically unsaturated monomers comprising:
  • Conjugated diene monomers (a) suitable for the preparation of the polymer latex according to the present invention may include conjugated diene monomers, selected from 1 ,3- butadiene, isoprene, 2,3-dimethyl-1 ,3-butadiene, 2-chloro-1 ,3-butadiene, 1 ,3-pentadiene,
  • 1 .3-butadiene is the most preferred diene.
  • the amount of conjugated diene monomer (a) ranges from 15 to 99 wt.-%, preferably from 20 to 95 wt.-%, more preferably from 30 to 75 wt.-%, most preferably from 40 to 70 wt.-%, based on the total weight of the ethylenically unsaturated monomers in the monomer mixture.
  • the conjugated diene monomer (a) may be present in amounts of at least 15 wt.-%, at least 20 wt.-%, at least 22 wt.-%, at least 24 wt.-%, at least 26 wt.-%, at least 28 wt.-%, at least 30 wt.-%, at least 32 wt.-%, at least 34 wt.-%, at least 36 wt.-%, at least 38 wt.-%, or at least 40 wt.-%, based on the total weight of the ethylenically unsaturated monomers in the monomer mixture.
  • the conjugated diene monomers (a) can be used in amounts of no more than 99 wt.-%, no more than 95 wt.-%, no more than 90 wt.-%, no more than 85 wt.-%, no more than 80 wt.-%, no more than 78 wt.-%, no more than 76 wt.-%, no more than 74 wt.-%, no more than 72 wt.-%, no more than 70 wt.-%, no more than 68 wt.-%, no more than 66 wt.-%, no more than 64 wt.-%, no more than 62 wt.-%, no more than 60 wt.-%, no more than 58 wt.-%, or no more than 56 wt.-%, based on the total weight of the ethylenically unsaturated monomers in the monomer mixture.
  • the latex particles exhibit a gradient of the concentration of the functional group (a) with a higher concentration of functional groups (a) at the surface of the particles and a lower concentration within the bulk of the particles.
  • Ethylenically unsaturated nitrile monomers (b) which can be used in the present invention may include polymerizable unsaturated aliphatic nitrile monomers which contain from 2 to 4 carbon atoms in a linear or branched arrangement, which may be substituted either by acetyl or additional nitrile groups.
  • the ethylenically unsaturated nitrile monomers (b) for the preparation of particles of a polymer latex according to the present invention may be selected from acrylonitrile, methacrylonitrile, alpha-cyanoethyl acrylonitrile, fumaronitrile, alpha-chloronitrile and combinations thereof, with acrylonitrile being most preferred.
  • nitrile monomers (b) can be included in amounts from 1 to 80 wt.-%, preferably from 10 to 70 wt.-%, or 1 to 60 wt.-%, and more preferred from 15 to 50 wt.-%, even more preferred from 20 to 50 wt.-%, most preferred from 23 to 43 wt.-%, based on the total weight of the ethylenically unsaturated monomers in the monomer mixture.
  • the unsaturated nitrile (b) may be present in amounts of at least 1 wt.-%, at least 5 wt.-%, at least 10 wt.-%, at least 12 wt.-%, at least 14 wt.-%, at least 15 wt.-%, at least 16 wt.-%, at least 18 wt.-%, at least 20 wt.-%, at least 22 wt.-%, at least 23 wt.-%at least 24 wt.-%, at least 26 wt.-%, at least 28 wt.-%, at least 30 wt.-%, at least 32 wt.-%, at least 34 wt.-%, at least 36 wt.-%, at least 38 wt.-%, or at least 40 wt.-%, based on the total weight of the ethylenically unsaturated monomers in the monomer mixture.
  • the unsaturated nitrile monomers (b) can be used in amounts of no more than 80 wt.-%, no more than 75 wt.-%, no more than 73 wt.-%, no more than 70 wt.-%, no more than 68 wt.-%, no more than 66 wt.-%, no more than 64 wt.-%, no more than 62 wt.-%, no more than 60 wt.-%, no more than 58 wt.-%, no more than 56 wt.-%, no more than 54 wt.-%, no more than 52 wt.-%, no more than 50 wt.-%, no more than 48 wt.-%, no more than 46 wt.-%, or no more than 44 wt.- %, no more than 43 wt.-%, based on the total weight of the ethylenically unsaturated monomers in the monomer mixture.
  • Suitable vinyl-aromatic monomers (c) may be selected from styrene, oc-methylstyrene, vinyltoluene, o-methylstyrene, p-methylstyrene, p-tert-butylstyrene, 2,4-dimethylstyrene, 2- methylstyrene, 3-methylstyrene, 4-methylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-ethylstyrene, 2,4-diisopropylstyrene, 2,4-dimethylstyrene, 4-tert-butylstyrene, 5-tert- butyl-2-methylstyrene, 2-chlorostyrene, 3-chlorostyrene, 4-chlorostyrene, 4-bromostyrene, 2-methyl-4,6-dichlorostyrene, 2,4-dibro
  • the vinyl-aromatic compounds (c) can be used in a range of from 0 to 70 wt.-%, preferably from 1 to 70 wt.-%, more preferred from 10 to 70 wt.-%, even more preferred from 15 to 60 wt.-%, most preferred from 15 to 50 wt.-%, or from 0 to 25 wt.-%, more preferred from 0 to 15 wt.-%, and even more preferred from 0 to 10 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture.
  • the vinyl-aromatic compound (c) can be present in an amount of no more than 70 wt.-%, no more than 60 wt.-%, no more than 50 wt.-%, no more than 40 wt.-%, no more than 35 wt.-%, no more than 30 wt.-%, no more than 25 wt.-%, no more than 20 wt.-%, no more than 18 wt.-%, no more than 16 wt.-%, no more than 14 wt.-%, no more than 12 wt.-%, no more than 10 wt.-%, no more than 8 wt.-%, no more than 6 wt.-%, no more than 4 wt.-%, no more than 2 wt.-%, or no more than 1 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture.
  • the vinyl aromatic compound (c) may be present in amounts of at least 1 wt.-%, at least 2 wt.-%, at least 5 wt.-%, at least 10 wt.-%, at least 15 wt.-%, at least 20 wt.-%, at least 25 wt.-%, at least 30 wt.-%, or at least 35 wt.-% based on the total weight of ethylenically unsaturated monomers in the monomer mixture.
  • a person skilled in the art will appreciate that any range between any of the explicitly disclosed lower and upper limit is herein disclosed.
  • the sum of ethylenically unsaturated nitrile monomers (b) and vinyl aromatic monomers (c) is 0.95 to 84.95 wt.-% based on the total monomers in the mixture.
  • vinyl-aromatic compounds may also be completely absent.
  • ethylenically unsaturated nitrile monomers are mandatorily present and the latex may be considered as a XNBR latex.
  • ethylenically unsaturated nitrile monomers may be completely absent.
  • the monomer mixture of ethylenically unsaturated monomers for the preparation of the polymer latex of the present invention comprises 2.5 to 10.0 wt.-% of an ethylenically unsaturated acid (d) comprising an acid functional group; and a spacer group separating the ethylenically unsaturated group and the acid functional group by at least 4 atoms.
  • the acid functional group of the ethylenically unsaturated acid (d) may be selected from carboxylic acid groups and phosphorous containing acid groups. Suitable phosphorous containing acid groups may be selected from phosphoric acid groups and phosphonic acid groups. Preferably, the acid functional group of the ethylenically unsaturated acid (d) is selected from carboxylic acid groups.
  • the ethylenically unsaturated acid (d) may be selected from compounds having the structure:
  • R 1 is selected from H and Ci-C 4 alkyl
  • R 2 is selected from H or - A - X;
  • A is a divalent spacer group separating the ethylenically unsaturated group and the functional group X by at least 4 atoms independently at each occurrence selected from: - (C(O) - W) n - Y - (O) m - and - (CH 2 ) k - O - (C(O)) P - Y - (O) m -; wherein n, m, k and p are integers independently at each occurrence selected from 0 or 1 ; W is - O - or - NR 3 -;
  • R 3 is selected from H and Ci-C 4 alkyl
  • Y is selected from optionally substituted linear, branched, cyclic or aromatic C 2 to C 3 o divalent hydrocarbon or hetero hydrocarbon groups;
  • X is selected from - C(O)OH and - P(O)(OH) 2 , preferably - C(O)OH; with the proviso that if X is - C(O)OH m is 0; or
  • a - X is selected from - C(O) -O - (Y -C(O) - O)i - H, wherein I is an integer from 2 to 10, preferably from 2 to 7; and mixtures thereof.
  • the ethylenically unsaturated acid (d) is selected from carboxy (C 2 -C 3 o)alkyl (meth)acrylates, C7 to C15 fatty acids having a terminal ethylenically unsaturated group mono (meth)acryloyloxy alkyl esters of dicarboxylic esters and more preferred from carboxy (C 2 -Ci 2 )alkyl (meth)acrylates and omega-(meth)acryloyoloxy (C 2 -Ci 2 )alkyl succinates.
  • carboxy (C 2 -C 3 o)alkyl (meth)acrylates C7 to C15 fatty acids having a terminal ethylenically unsaturated group mono (meth)acryloyloxy alkyl esters of dicarboxylic esters and more preferred from carboxy (C 2 -Ci 2 )alkyl (meth)acrylates and omega-(meth)acryloyoloxy (C 2 -C
  • Suitable monomers of ethylenically unsaturated acid (d) are commercially available from Solvay (Belgium) as Sipomer® p-CEA, Sipomer® PAM 100, Sipomer® PAM 200, Sipomer® PAM 300, Sipomer® PAM 4000, and Sipomer® PAM 5000.
  • the amount of ethylenically unsaturated acids (d) is from 2.5 to 10.0 wt.-%, particularly from 3.0 to 8.5 wt.-% or 4.5 to 9.0 wt.-%, preferably from 3.4 to 8.0 wt.-%, more preferred from 3.6 to 7.0 wt.-%, even more preferred from 3.6 to 6.5 wt.-%, most preferred 3.6 to 6.0 wt.-%, based on the total weight of the ethylenically unsaturated monomers in the monomer mixture.
  • the ethylenically unsaturated acid (d) may be present in amounts of at least 2.5 wt.-%, at least 2.7 wt.-%, at least 2.9 wt.-%, at least 3.0 wt.-%, at least 3.2 wt.-%, at least 3.4 wt.-%, at least 3.5 wt.-%, at least 3.6 wt.-%, at least 3.8 wt.-%, at least 3.9 wt.-%, at least 4.0 wt.-%, at least 4.1 wt.-%, at least 4.2 wt.-%, at least 4.3 wt.- %, at least 4.5 wt.-%, or at least 4.6 wt.-%, based on the total weight of the ethylenically unsaturated monomers in the monomer mixture.
  • the ethylenically unsaturated acid (d) may be present in amounts of no more than 10 wt.-%, no more than 9.5 wt.-%, no more than 9.0 wt.-%, no more than 8.5 wt.-%, no more than 8.0 wt.-%, no more than 7.5 wt.-%, no more than 7.0 wt.-%, no more than 6.5 wt.-%, no more than 6.0 wt.-%, no more than 5.5 wt.-%, or no more than 5.0 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture.
  • a person skilled in the art will appreciate that any range defined by an explicitly disclosed lower limit and an explicitly disclosed upper limit is disclosed herewith.
  • the mixture of ethylenically unsaturated monomers for the preparation of the polymer latex of the present invention may further comprise (f) an ethylenically unsaturated acid being different from the ethylenically unsaturated acid (d).
  • the acid functional group of the ethylenically unsaturated acid (f) may be selected from carboxylic acid groups and phosphorous containing acid groups. Suitable phosphorous containing acid groups may be selected from phosphoric acid groups and phosphonic acid groups.
  • the acid functional group of the ethylenically unsaturated acid (f) is selected from carboxylic acid groups.
  • the ethylenically unsaturated acid (f) can be used in a range of from 0 to 10.0 wt.-%, preferably from 0 to 9.0 wt.-%, more preferred from 0 to 7.0 wt.-%, even more preferred from 0 to 5.0 wt.-%, most preferred from 0 to 3.5 wt.-%, or from 0.5 to 3.5 wt.-%, more preferred from 0.5 to 3.0 wt.-%, and even more preferred from 0.5 to 2.5 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture.
  • the ethylenically unsaturated acid (f) can be present in an amount of no more than 10.0 wt.-%, no more than 9.5 wt.-%, no more than 8.0 wt.-%, no more than 7.5 wt.-%, 7.0 wt.-%, no more than 6.5 wt.-%, no more than 6.0 wt.-%, no more than 5.5 wt.-%, no more than 5.0 wt.-%, no more than 4.5 wt.-%, no more than 4.2 wt.-%, no more than 4.0 wt.-%, no more than 3.8 wt.-%, no more than 3.6 wt.-%, no more than 3.5 wt.-%, no more than 3.2 wt.-%, no more than 3.0 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture.
  • the vinyl aromatic compound may be present in amounts of at least 0.1 wt.-%, at least 0.5 wt.-%, at least 0.7 wt.-%, at least 1 wt.-%, at least 1 .2 wt.-%, at least 1 .3 wt.-%, at least 1 .5 wt.-%, at least 1 .7 wt.-%, or at least 2.0 wt.- %, based on the total weight of ethylenically unsaturated monomers in the monomer mixture.
  • a person skilled in the art will appreciate that any range between any of the explicitly disclosed lower and upper limit is herein disclosed.
  • the ethylenically unsaturated acid (d) and the ethylenically unsaturated acid (f) may be present in an amount in the range of up to 10.0 wt.-%, up to 9.5 wt.-%, up to 9.0 wt.-%, up to 8.5 wt.-%, up to 8.0 wt.-%, up to 7.5 wt.- %, up to 7.0 wt.-%, up to 6.5 wt.-%, up to 6.0 wt.-%, up to 5.5 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture.
  • the ethylenically unsaturated acid (d) and the ethylenically unsaturated acid (f) may be present in an amount in the range of at least 3.0 wt.-%, at least 3.2 wt.-%, at least 3.5 wt.-%, at least 3.8 wt.-%, at least 4.0 wt.-%, at least 4.2 wt.-%, at least 4.5 wt.-%, at least 4.8 wt.-%, at least 5.0 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture.
  • a person skilled in the art will appreciate that any range between any of the explicitly disclosed lower and upper limit is herein disclosed.
  • the ethylenically unsaturated acid (d) and the ethylenically unsaturated acid (f) may be present in an amount in the range of from 3.0 to 10.0 wt.-%, preferably from 3.5 to 10.0 wt.-%, more preferably from 4.0 to 9.0 wt.-%, even more preferably from 4.5 to 8.0 wt.-%, most preferably from 5.0 to 7.0 wt.- %, based on the total weight of ethylenically unsaturated monomers in the monomer mixture.
  • the ethylenically unsaturated acid (d) and the ethylenically unsaturated acid (f) may be present in an amount in the range of up to 10.0 wt.-%, preferably up to 9.0 wt.-%, more preferably up to 8.0 wt.-%, even more preferably up to 7.0 wt.-%, most preferably up to 6.0 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture.
  • the ethylenically unsaturated acid (d) may be the sole ethylenically unsaturated acid.
  • the ethylenically unsaturated acid (f) or salts may be selected from ethylenically unsaturated carboxylic acids and salts thereof, such as monocarboxylic acid and dicarboxylic acid monomers; ethylenically unsaturated polycarboxylic acid anhydride; and polycarboxylic acid partial ester monomers and salts thereof. It is preferable to use ethylenically unsaturated aliphatic mono- or dicarboxylic acids or anhydrides which contain from 3 to 5 carbon atoms.
  • Ethylenically unsaturated carboxylic acids and salts thereof may be selected from (meth)acrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, cis-cyclohexene-1 ,2-dicarboxylic acid, dimethylmaleic acid, bromomaleic acid, 2,3-dichloromaleic acid and (2-dodecen-1 -yl) succinic acid, vinyl acetic acid, vinyl lactic acid, vinyl sulfonic acid, 2-methyl-2-propene-1 - sulfonic acid, styrene sulfonic acid, acrylamidomethyl propane sulfonic acid and salts thereof; preferably (meth)acrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, and salts thereof.
  • Ethylenically unsaturated polycarboxylic acid anhydride may be selected from maleic anhydride, methacrylic anhydride, cis-cyclohexene-1 ,2-dicarboxylic anhydride, dimethylmaleic anhydride, bromomaleic anhydride, 2,3-dichloromaleic anhydride, citraconic anhydride, crotonic anhydride, itaconic anhydride, and (2-dodecen-1 -yl) succinic anhydride.
  • Polycarboxylic acid partial ester monomers and salts thereof may be selected from monomethyl maleate, monomethyl fumarate, monoethyl maleate, monoethyl fumarate, monopropyl maleate, monopropyl fumarate, monobutyl maleate, monobutyl fumarate, mono(2-ethyl hexyl) maleate, mono(2-ethyl hexyl) fumarate and combinations thereof.
  • the monomer mixture of ethylenically unsaturated monomers to obtain the polymer latex of the present invention may comprise co-polymerizable ethylenically unsaturated compounds (e).
  • the co-polymerizable ethylenically unsaturated compounds (e) can be used in a range of from 0 to 65 wt.-%, preferably from 1 to 65 wt.-%, more preferred from 10 to 55 wt.-%, even more preferred from 15 to 50 wt.-%, most preferred from 15 to 40 wt.-%, or from 0 to 25 wt.-%, more preferred from 0 to 15 wt.-%, and even more preferred from 0 to 10 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture.
  • the co-polymerizable ethylenically unsaturated compounds (e) can be present in an amount of no more than 65 wt.-%, no more than 60 wt.-%, no more than 50 wt.-%, no more than 40 wt.-%, no more than 35 wt.-%, no more than 30 wt.-%, no more than 25 wt.-%, no more than 20 wt.-%, no more than 18 wt.-%, no more than 16 wt.-%, no more than 14 wt.- %, no more than 12 wt.-%, no more than 10 wt.-%, no more than 8 wt.-%, no more than 6 wt.-%, no more than 4 wt.-%, no more than 2 wt.-%, or no more than 1 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture
  • the co- polymerizable ethylenically unsaturated compounds (e) may be present in amounts of at least 1 wt.-%, at least 2 wt.-%, at least 5 wt.-%, at least 10 wt.-%, at least 15 wt.-%, at least 20 wt.-%, at least 25 wt.-%, at least 30 wt.-%, or at least 35 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture.
  • a person skilled in the art will appreciate that any range between any of the explicitly disclosed lower and upper limit is herein disclosed.
  • the co-polymerizable ethylenically unsaturated compounds (e) may be selected from
  • Alkyl esters of ethylenically unsaturated acids (e1 ) that can be used according to the present invention may include n-alkyl esters, iso-alkyl esters or tert-alkyl esters of (meth)acrylic acid in which the alkyl group has from 1 to 20 carbon atoms, the reaction product of methacrylic acid with glycidyl ester of a neoacid such as versatic acid, neodecanoic acid or pivalic acid and hydroxyalkyl (meth)acrylate and alkoxyalkyl (meth)acrylate monomers.
  • the preferred alkyl esters of ethylenically unsaturated acids (e1 ) may be selected from C1-C10 alkyl (meth)acrylate, preferably Ci-Cs-alkyl (meth)acrylates.
  • (meth)acrylate monomers include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, iso-propyl (meth)acrylate, n-butyl (meth)acrylate, secondary butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, hexyl (meth)acrylate, 2-ethyl-hexyl (meth)acrylate, isooctyl (meth)acrylate, 4-methyl-2-pentyl (meth) acrylate, 2-methylbutyl (meth)acrylate, cyclohexyl (meth)acrylate, cet
  • the alkyl esters of ethylenically unsaturated acids (e1 ) can be present in an amount of no more than 18 wt.-%, no more than 16 wt.-%, no more than 14 wt.-%, no more than 12 wt.-%, no more than 10 wt.-%, no more than 8 wt.-%, no more than 6 wt.-%, no more than 4 wt.-%, no more than 2 wt.-%, or no more than 1 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture.
  • the hydroxyalkyl esters of ethylenically unsaturated acids (e2) which can be used to prepare the polymer latex according to the present invention, may include hydroxyalkyl acrylate and methacrylate monomers which are based on ethylene oxide, propylene oxide and higher alkylene oxides or mixtures thereof.
  • Suitable examples of hydroxyalkyl esters of ethylenically unsaturated acids (e2) may be selected from hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, and combinations thereof.
  • the hydroxyalkyl esters of ethylenically unsaturated acids (e2) is 2-hydroxy ethyl(meth)acrylate.
  • hydroxyalkyl esters of ethylenically unsaturated acids (e2) can be present in an amount of no more than 18 wt.-%, no more than 16 wt.-%, no more than 14 wt.-%, no more than 12 wt.-%, no more than 10 wt.-%, no more than 8 wt.-%, no more than 6 wt.-%, no more than 4 wt.-%, no more than 2 wt.-%, or no more than 1 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture.
  • Amides of ethylenically unsaturated acids (e3) that can be used for the preparation of the polymer latex according to the present invention may be selected from (meth)acryl amide, diacetone acrylamide, and combinations thereof.
  • the preferred amide monomer is (meth)acrylamide.
  • monomers comprising N-methylol amide groups may be employed.
  • Suitable monomers are N-methylol (meth)acrylamide, N-methoxymethyl (meth)acrylamide, N-n-butoxy-methyl (meth)acrylamide, N-iso-butoxy-methyl (meth)acrylamide, N-acetoxymethyl (meth)acrylamide, N-(2,2-dimethoxy-1 -hydroxyethyl) acrylamide.
  • amides of ethylenically unsaturated acids can be present in an amount of no more than 18 wt.-%, no more than 16 wt.-%, no more than 14 wt.-%, no more than 12 wt.-%, no more than 10 wt.-%, no more than 8 wt.-%, no more than 6 wt.-%, no more than 4 wt.-%, no more than 2 wt.-%, or no more than 1 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture.
  • Vinyl carboxylates (e4) which can be used according to the present invention, may be selected from vinyl acetate, vinyl propionate, vinyl butyrate, vinyl benzoate, vinyl-2- ethylhexanoate, vinyl stearate, vinyl esters of versatic acid, and combinations thereof.
  • the most preferred vinyl carboxylate monomer (e4) for use in the present invention is vinyl acetate.
  • the vinyl carboxylates (e4) can be present in an amount of no more than 18 wt.-%, no more than 16 wt.-%, no more than 14 wt.-%, no more than 12 wt.-%, no more than 10 wt.-%, no more than 8 wt.-%, no more than 6 wt.-%, no more than 4 wt.-%, no more than 2 wt.-%, or no more than 1 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture.
  • Alkoxyalkyl esters of ethylenically unsaturated acids (e5) which can be used in the present invention may be selected from methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, methoxybutyl (meth)acrylate, methoxyethoxyethyl (meth)acrylate and combinations thereof.
  • Preferred alkoxyalkyl esters of ethylenically unsaturated acids (e5) are ethoxyethyl acrylate and methoxyethyl acrylate.
  • the alkoxyalkyl esters of ethylenically unsaturated acids (e5) can be present in an amount of no more than 18 wt.-%, no more than 16 wt.-%, no more than 14 wt.-%, no more than 12 wt.-%, no more than 10 wt.-%, no more than 8 wt.-%, no more than 6 wt.-%, no more than 4 wt.-%, no more than 2 wt.-%, or no more than 1 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture.
  • Suitable monomers having at least two ethylenically unsaturated groups (e6) may be selected from divinyl benzene and di(meth)acrylates, such as ethylene glycol di(meth)acrylate, hexanediol di(meth)acrylate, tripropylene glycol di(meth)acrylate, butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, and dipropylene glycol di(meth)acrylate.
  • di(meth)acrylates such as ethylene glycol di(meth)acrylate, hexanediol di(meth)acrylate, tripropylene glycol di(meth)acrylate, butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, diethylene glycol di(meth)acryl
  • the monomers having at least two ethylenically unsaturated groups (e6) are preferably selected from divinyl benzene, 1 ,2-ethyleneglycol di(meth)acrylate, 1 ,4-butanediol di(meth)acrylate and 1 ,6-hexanediol di(meth)acrylate. More preferred monomers having at least two ethylenically unsaturated groups (e6) may be selected from divinyl benzene, ethylene glycol dimethacrylate and 1 ,4 butanediol di(meth)acrylate.
  • the monomers having at least two ethylenically unsaturated groups (6) may be present in an amount of less than 5 wt.-%, preferably less than 4 wt.-%, particularly preferred less than 3 wt.-%, more preferred less than 2.5 wt.-%, even more preferred less than 2 wt.-%, most preferred less than 1.5 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture.
  • the monomer mixture may be free of monomers having at least two ethylenically unsaturated groups (e6).
  • Suitable ethylenically unsaturated silanes (e7) may be selected from vinyl trialkoxysilanes, allyl trialkoxysilanes, 3-(meth)acryloxy propyl trialkoxysilanes and combinations thereof.
  • the ethylenically unsaturated silanes (e7) may be present in an amount of less than 5 wt.- %, preferably less than 4 wt.-%, more preferred less than 3 wt.-%, even more preferred less than 2.5 wt.-%, even more preferred less than 2 wt.-%, even more preferred less than 1 .5 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture.
  • the monomer mixture may be free of ethylenically unsaturated silanes (e7).
  • the amounts of the above-defined monomers for the preparation of the latex polymer may add up to 100 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture.
  • the mixture of ethylenically unsaturated monomers to obtain the latex polymer of the present invention may comprise:
  • conjugated dienes preferably selected from butadiene, isoprene and combinations, thereof, more preferred butadiene;
  • (f) 0 to 10.0 wt.-% of ethylenically unsaturated acids different from (d), the weight percentages being based on the total weight of the ethylenically unsaturated monomers in the monomer mixture.
  • the amounts of the above-defined monomers for the preparation of polymer latex may add up to 100 wt.-%.
  • the latex polymer may be free of any ethylenically unsaturated acids different from (d).
  • the polymer latex composition of the present invention may be substantially free of a biocide.
  • the term “substantially free” means that the biocide is present, if at all, as an incidental impurity, such as in an amount of less than 0.04 wt.-%, based on the total weight of the polymer latex composition.
  • the polymer latex composition may be completely free of a biocide.
  • the term “completely free” means that a biocide is not present in the polymer latex composition at all.
  • biocide refers to compounds used to prevent the growth and/or to inhibit unwanted microorganisms selected from the group comprising at least one strain of bacteria, at least one strain of fungi, mould, yeast, algae and mixtures thereof.
  • biocides may be selected from the group comprising phenols, such as 2-phenylphenol or 2-phenylphenol in the form of an alkali metal salt such as sodium salt or potassium salt; halogenated phenols, such as 4-chloro-3-methylphenol or 4-chloro-2- methylphenol; halogen-containing compounds or halogen-releasing compounds, such as bronopol, bronidox, 2,2-dibrom-3-nitrilpropionamid, 1 ,2- dibromo-2,4-dicyanobutane, monochloroamine, ammonium bromide, calcium hypochlorite, iodine, tri-iodide or potassium iodate; isothiazolinones, such as isothiazolinone, benzisothiazolinone, 5-chloro- 2-methyl-2H-isothiazolin-3-one, 2-methyl-2H-isothiazolin-3-one, octylisothiazolin
  • the pH of the polymer latex composition of the present invention is lower than 7.5, preferably lower than or equal to 7.4, more preferably lower than or equal to 7.2, even more preferably lower than or equal to 7.1 , most preferably lower than or equal to 7.0.
  • the pH of the polymer latex composition of the present invention may be at least 2.0, at least 2.5, at least 3.0, at least 3.5, at least 4.0, at least 4.5, at least 5.0, at least 5.5, at least 5.8, at least 6.0, at least 6.2, at least 6.4, at least 6.5.
  • the pH of the polymer latex composition of the present invention may be up to 7.4, up to 7.3, up to 7.2, up to 7.1 , up to 7.0, up to 6.9.
  • the pH of the polymer latex composition of the present invention may be in the range of 6.0 to less than 7.5, preferably 6.0 to 7.4, more preferably 6.0 to 7.2, even more preferably 6.5 to 7.2, most preferably 6.7 to 7.2.
  • the pH may be determined according to DIN ISO 976.
  • the pH may be adjusted using a pH modifier selected from sodium hydroxide, potassium hydroxide, ammonia solution, preferably ammonia solution.
  • the polymer latex composition of the present invention can be prepared by first making the polymer latex as described above and then combining the obtained polymer latex with an oxirane functional compound.
  • the carboxylic acid functional latex polymer of the present invention and the oxirane functional compound may be present in relative amounts to provide a molar ratio of oxirane groups to carboxylic acid groups from 0.1 to 2.0, preferably from 0.1 to 1.5, more preferred from 0.2 to 0.9, most preferred from 0.3 to 0.6.
  • the oxirane functional compound may be selected from i) a latex polymer, preferably a butadiene acrylonitrile latex polymer bearing a plurality of oxirane functional groups; ii) monomeric or oligomeric compounds comprising at least two oxirane functional groups; and iii) monomeric compounds, oligomeric or polymeric compounds that are not prepared be free-radical addition polymerization bearing at least one oxirane group and a functional group different from an oxirane group, said functional groups different from an oxirane group on different molecules of compound iii) are capable of reacting with each other.
  • the latex polymer i) may be selected from oxirane functional latex polymers as disclosed in WO 2017/209596.
  • Suitable monomeric or oligomeric compounds comprising at least two oxirane functional groups ii) may be selected from ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, poly (ethylene glycol) diglycidyl ether, polypropylene glycol) diglycidyl ether, bisphenol-A diglycidyl ether, and combinations thereof.
  • compound ill) is selected from oxirane functional di- or tri alkoxysilanes, more preferred from (3-glycidoxypropyl) trialkoxysilanes.
  • the method for preparing a polymer latex composition comprises preparing a polymer latex by free-radical emulsion polymerization of a mixture of ethylen ically unsaturated monomers comprising:
  • the polymer latex according to the present invention can be made by any emulsion polymerization process known to a person skilled in the art, provided that the monomer mixture as herein defined is employed. Particularly suitable is the process as described in EP-A 792 891.
  • a seed latex may be employed. Any seed particles as known to the person skilled in the art can be used.
  • the seed latex particles are preferably present in an amount of 0.01 to 10 parts by weight, preferably 1 to 5 parts by weight, based on 100 parts by weight of total ethylenically unsaturated monomers employed in the polymer.
  • the lower limit of the amount of seed latex particles therefore can be 0.01 , 0.05, 0.1 , 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1 .0, 1.1 , 1 .2, 1 .3, 1 .4, 1 .5, 1 .6, 1 .7, 1 .8, 1 .9, 2.0, 2.1 , 2.2, 2.3, 2.4, or 2.5 parts by weight.
  • the upper limit of the amount can be 10, 9, 8, 7, 6, 5.5, 5, 4.5, 4, 3.8, 3.6, 3.4, 3.3, 3.2, 3.1 or 3 parts by weight.
  • the process for the preparation of the above-described polymer latex can be performed at temperatures of from 0 to 130 °C, preferably of from 0 to 100 °C, particularly preferably of from 5 to 70 °C, very particularly preferably of from 5 to 60 °C, in the presence of no or one or more emulsifiers, no or one or more colloids and one or more initiators.
  • the temperature includes all values and sub-values therebetween, especially including 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120 and 125 °C.
  • Initiators which can be used when carrying out the present invention may include water- soluble and/or oil-soluble initiators which are effective for the purposes of the polymerization.
  • Representative initiators are well known in the technical area and include, for example: azo compounds (such as, for example, AIBN, AMBN and cyanovaleric acid) and inorganic peroxy compounds, such as hydrogen peroxide, sodium, potassium and ammonium peroxydisulfate, peroxycarbonates and peroxyborates, as well as organic peroxy compounds, such as alkyl hydroperoxides, dialkyl peroxides, acyl hydroperoxides, and diacyl peroxides, as well as esters, such as tert-butyl perbenzoate and combinations of inorganic and organic initiators.
  • azo compounds such as, for example, AIBN, AMBN and cyanovaleric acid
  • inorganic peroxy compounds such as hydrogen peroxide, sodium, potassium and ammonium peroxydisulfate, peroxycarbonates and
  • Suitable initiators may be selected from 2,3-dimethyl- 2,3-diphenylbutane, tert-butyl hydroperoxide, tert-amyl hydroperoxide, cumyl hydroperoxide, 1 ,1 ,3,3-tetramethylbutyl hydroperoxide, isopropylcumyl hydroperoxide, 2,5- di(tert-butylperoxy)-2,5-dimethyl-3-hexyne, 3,6,9-triethyl-3,6,9-trimethyl-1 ,4,7- triperoxonane, di(tert-butyl)peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, di(tert- butylperoxy-isopropyl)benzene, tert-butyl cumyl peroxide, di-(tert-amyl)-peroxide, dicumyl peroxide, butyl 4,4-
  • the initiator may be used in a sufficient amount to initiate the polymerization reaction at a desired rate.
  • an amount of initiator of from 0.01 to 5 wt.-%, preferably of from 0.1 to 4 wt.-%, based on the total weight of monomers in the monomer mixture, is sufficient.
  • the amount of initiator is most preferably of from 0.01 to 2 wt.-%, based on the total weight of monomers in the monomer mixture.
  • the amount of initiator includes all values and subvalues therebetween, especially including 0.01 , 0.1 , 0.5, 1 , 1.5, 2, 2.5, 3, 4 and 4.5 wt.-%, based on the total weight of monomers in the monomer mixture.
  • the above-mentioned inorganic and organic peroxy compounds may also be used alone or in combination with one or more suitable reducing agents, as is well known in the art.
  • suitable reducing agents may include sulfur dioxide, alkali metal disulfites, alkali metal and ammonium hydrogen sulfites, thiosulfates, dithionites and formaldehyde sulfoxylates, as well as hydroxylamine hydrochloride, hydrazine sulfate, iron (II) sulfate, cuprous naphthanate, glucose, sulfonic acid compounds such as sodium methane sulfonate, amine compounds such as dimethylaniline and ascorbic acid.
  • the quantity of the reducing agent is preferably 0.03 to 10 parts by weight per part by weight of the polymerization initiator.
  • Surfactants or emulsifiers which are suitable for stabilizing the latex particles may include those conventional surface-active agents for polymerization processes.
  • the surfactant or surfactants can be added to the aqueous phase and/or the monomer phase.
  • An effective amount of surfactant in a seed process is the amount which was chosen for supporting the stabilization of the particle as a colloid, the minimization of contact between the particles and the prevention of coagulation. In a non-seeded process, an effective amount of surfactant is the amount which was chosen for influencing the particle size.
  • Representative surfactants include saturated and ethylenically unsaturated sulfonic acids or salts thereof, including, for example, unsaturated hydrocarbonsulfonic acid, such as vinylsulfonic acid, allylsulfonic acid and methallylsulfonic acid, and salts thereof; aromatic hydrocarbon acids, such as, for example, p-styrenesulfonic acid, isopropenylbenzenesulfonic acid and vinyloxybenzenesulfonic acid and salts thereof; sulfoalkyl esters of acrylic acid and methacrylic acid, such as, for example, sulfoethyl methacrylate and sulfopropyl methacrylate and salts thereof, and 2-acrylamido-2- methylpropanesulfonic acid and salts thereof; alkylated diphenyl oxide disulfonates, sodium dodecylbenzenesulfonates and dihexyl esters of sodium sulfo
  • the type and the amount of the surfactant is governed typically by the number of particles, their size and their composition.
  • the surfactant is used in amounts of from 0 to 20 wt.-%, preferably from 0 to 10 wt.-%, more preferably from 0 to 5 wt.-%, based on the total weight of the monomers in the monomer mixture.
  • the amount of surfactant includes all values and sub-values therebetween, especially including 0, 0.1 , 0.5, 1 , 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 , 12, 13, 14, 15, 16, 17, 18 and 19 wt.-%, based on the total weight of the monomer in the monomer composition.
  • the polymerization may be conducted without using surfactants.
  • Suitable colloids include polyhydroxy compounds, such as partially acetylated polyvinyl alcohol, casein, hydroxyethyl starch, carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, polysaccharides, and degraded polysaccharides, polyethylene glycol and gum arable.
  • the preferred protective colloids are carboxymethylcellulose, hydroxyethylcellulose and hydroxypropylcellulose.
  • these protective colloids are used in contents of from 0 to 10 parts by weight, preferably from 0 to 5 parts by weight, more preferably from 0 to 2 parts by weight, based on the total weight of the monomers.
  • the amount of protective colloids includes all values and subvalues therebetween, especially including 1 , 2, 3, 4, 5, 6, 7, 8 and 9 wt.-%, based on the total weight of the monomers.
  • the polymer latex composition of the present invention has a certain maximum electrolyte stability determined as critical coagulation concentration of less than 30 mmol/l CaCI 2 , preferably less than 25 mmol/l CaCI 2 , more preferred less than 20 mmol/l CaCI 2 , most preferred less than 10 mmol/l CaCI 2 (determined for a total solids content of the composition of 0.1% at pH 10 and 23°C).
  • the electrolyte stability will depend on certain different factors, for example, amount and selection of monomers to be used for making the polymer latex, especially monomers containing polar-functional groups, as well as the selection and amount of the stabilizing system, for example, the emulsion polymerization process for making the polymer latex.
  • the stabilizing system may contain surface-active agents and/or protective colloids.
  • a person skilled in the art is able, depending on the selected monomers and their relative amounts for making the polymer latex of the present invention, to adjust the stabilizing system in order to achieve an electrolyte stability according to the present invention.
  • buffer substances and chelating agents are, for example, alkali metal phosphates and pyrophosphates (buffer substances) and the alkali metal salts of ethylenediaminetetraacetic acid (EDTA) or hydroxyl-2-ethylenediaminetriacetic acid (HEEDTA) as chelating agents.
  • EDTA ethylenediaminetetraacetic acid
  • HEEDTA hydroxyl-2-ethylenediaminetriacetic acid
  • the quantity of buffer substances and chelating agents is usually 0.001 -1.0 wt.-%, based on the total quantity of monomers.
  • chain transfer agents emulsion polymerization
  • Typical agents are, for example, organic sulfur compounds, such as thioesters, 2-mercaptoethanol, 3-mercaptopropionic acid and C1-C12 alkyl mercaptans, n-dodecylmercaptan and t-dodecylmercaptan being preferred.
  • the quantity of chain transfer agents, if present, is usually 0.05-3.0 wt.-%, preferably 0.2-2.0 wt.-%, based on the total weight of the used monomers.
  • additives and ingredients can be added in order to prepare the latex composition of the present invention.
  • additives include, for example: antifoams, wetting agents, thickeners, plasticizers, fillers, pigments, dispersants, optical brighteners, crosslinking agents, accelerators, antioxidants, biocides and metal chelating agents.
  • antifoams include silicone oils and acetylene glycols.
  • Customary known wetting agents include alkylphenol ethoxylates, alkali metal dialkylsulfosuccinates, acetylene glycols and alkali metal alkylsulfate.
  • Typical thickeners include polyacrylates, polyacrylamides, xanthan gums, modified celluloses or particulate thickeners, such as silicas and clays.
  • Typical plasticizers include mineral oil, liquid polybutenes, liquid polyacrylates and lanolin.
  • Zinc oxide is a suitable crosslinking agent. Titanium dioxide (TiOz), calcium carbonate and clay are the fillers typically used.
  • Known accelerators and secondary accelerators include dithiocarbamates like zinc diethyl dithiocarbamate, zinc dibutyl dithiocarbamate, zinc dibenyl dithiocarbamate, zinc pentamethylene dithiocarbamate (ZPD), xanthates, thiurams like tetramethylthiuram monosulfide (TMTM), tetramethylthiuram disulfide (TMTD), tetraethylthiuram disulfide (TETD), dipentamethylenethiuram hexasulfide (DPTT), and amines, such as diphenylguanidine (DPG), di-o-tolylguanidine (DOTG), and o-tolylbiguanidine (OTBG).
  • the polymer latex composition is free of any biocides.
  • the polymer latex of the present invention is particularly suitable for dip-molding processes. Therefore, the polymer latex or the polymer latex composition of the present invention is compounded to produce a curable polymer latex compound composition that can be directly used in dip-molding processes.
  • the compounded latex composition suitable for the production of dip-molded articles comprises the polymer latex composition of the present invention or obtained by the method for preparing a polymer latex composition of the present invention.
  • the monomer mixture may further comprise an ethylenically unsaturated acid (f).
  • the ethylenically unsaturated acid (f) can be present in an amount of no more than 10.0 wt.-%, no more than 9.5 wt.-%, no more than 8.0 wt.-%, no more than 7.5 wt.-%, 7.0 wt.-%, no more than 6.5 wt.-%, no more than 6.0 wt.-%, no more than 5.5 wt.-%, no more than 5.0 wt.-%, no more than 4.5 wt.-%, no more than 4.2 wt.-%, no more than 4.0 wt.- %, no more than 3.8 wt.-%, no more than 3.6 wt.-%, no more than 3.5 wt.-%, no more than 3.2 wt.-%, no more than 3.0 wt.-%, based on the total
  • the ethylenically unsaturated acid (f) may be present in amounts of at least 0.1 wt.-%, at least 0.5 wt.-%, at least 0.7 wt.-%, at least 1 wt.-%, at least 1 .2 wt.-%, at least 1 .3 wt.-%, at least 1 .5 wt.-%, at least 1 .7 wt.-%, or at least 2.0 wt.-% based on the total weight of ethylenically unsaturated monomers in the monomer mixture.
  • a person skilled in the art will appreciate that any range between any of the explicitly disclosed lower and upper limit is herein disclosed.
  • the ethylenically unsaturated acid (f) can be present in a range of from 0.1 to 10.0 wt.-%, preferably from 0.1 to 9.0 wt.-%, more preferred from 0.1 to 7.0 wt.-%, even more preferred from 0.5 to 5.0 wt.-%, most preferred from 0.5 to 3.5 wt.-%, or from 0.5 to 3.5 wt.-%, more preferred from 0.5 to 3.0 wt.-%, and even more preferred from 0.5 to 2.5 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture.
  • the ethylenically unsaturated acid (d) and the ethylenically unsaturated acid (f) may be present in an amount in the range of up to 10.0 wt.-%, up to 9.5 wt.-%, up to 9.0 wt.-%, up to 8.5 wt.-%, up to 8.0 wt.-%, up to 7.5 wt.- %, up to 7.0 wt.-%, up to 6.5 wt.-%, up to 6.0 wt.-%, up to 5.5 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture.
  • the ethylenically unsaturated acid (d) and the ethylenically unsaturated acid (f) may be present in an amount in the range of at least 3.0 wt.-%, at least 3.2 wt.-%, at least 3.5 wt.-%, at least 3.8 wt.-%, at least 4.0 wt.-%, at least 4.2 wt.-%, at least 4.5 wt.-%, at least 4.8 wt.-%, at least 5.0 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture.
  • a person skilled in the art will appreciate that any range between any of the explicitly disclosed lower and upper limit is herein disclosed.
  • the ethylenically unsaturated acid (d) and the ethylenically unsaturated acid (f) may be present in an amount in the range of from 3.0 to 10.0 wt.-%, preferably from 3.5 to 10.0 wt.-%, more preferably from 4.0 to 9.0 wt.-%, even more preferably from 4.5 to 8.0 wt.-%, most preferably from 5.0 to 7.0 wt.- %, based on the total weight of ethylenically unsaturated monomers in the monomer mixture.
  • the ethylenically unsaturated acid (d) and the ethylenically unsaturated acid (f) may be present in an amount in the range of up to 10.0 wt.-%, preferably up to 9.0 wt.-%, more preferably up to 8.0 wt.-%, even more preferably up to 7.0 wt.-%, most preferably up to 6.0 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture.
  • the ethylenically unsaturated acid (d) may be the sole ethylenically unsaturated acid.
  • the compounded latex composition may further comprise adjuvants selected from sulfur vulcanization agents, accelerators for sulfur vulcanization, crosslinkers, polyvalent cations and combinations thereof.
  • adjuvants selected from sulfur vulcanization agents, accelerators for sulfur vulcanization, crosslinkers, polyvalent cations and combinations thereof.
  • multivalent cations preferably ZnO, preferably in amounts of 0.5 wt.-% to 2.5 wt.-% of ZnO based on solid latex polymer of ZnO is preferred.
  • the compounded latex composition of the present invention may comprise 0 to 2.8 wt.-%, preferably 0.5 to 2.8 wt.-%, more preferred 1 .0 to 2.0 wt.-%, most preferred 1 .5 to 2.0 wt.-% sulfur and 0.0 to 2.8 wt.-%, preferably 1 .0 to 2.0 wt.-%, more preferred 1 .2 to 1.8 wt.-% of sulfur vulcanization agents and 0.5 wt.-% to 2.5 wt.-% of ZnO the weight percentages being based on solid latex polymer. If crosslinkers such as the oxirane functional compounds as discussed above are present sulfur vulcanization agents may be omitted.
  • the compounded polymer latex composition contains the polymer latex of the present invention, optionally the pH modifiers, preferably ammonia or alkali hydroxides and optionally usual additives to be used in these compositions selected from antioxidants, pigments, TiO2, fillers and dispersing agents.
  • additives and ingredients can be added in order to prepare the latex composition of the present invention.
  • additives include, for example: antifoams, wetting agents, thickeners, plasticizers, fillers, pigments, dispersants, optical brighteners, antioxidants, biocides and metal chelating agents.
  • the compounded polymer latex is substantially free of biocides and even more preferably the compounded polymer latex is completely free of biocides.
  • Known antifoams include silicone oils and acetylene glycols.
  • Customary known wetting agents include alkylphenol ethoxylates, alkali metal dialkylsulfosuccinates, acetylene glycols and alkali metal alkylsulfate.
  • Typical thickeners include polyacrylates, polyacrylamides, xanthan gums, modified celluloses or particulate thickeners, such as silicas and clays.
  • Typical plasticizers include mineral oil, liquid polybutenes, liquid polyacrylates and lanolin. Titanium dioxide (TiO 2 ), calcium carbonate and clay are the fillers typically used.
  • the present invention relates to a method for making dip-molded articles.
  • a clean mold having the desired shape of the final article is immersed in a coagulant bath comprising a solution of a metal salt.
  • the coagulant is usually used as a solution in water, an alcohol or a mixture thereof.
  • the metal salts can be metal halides like calcium chloride, magnesium chloride, barium chloride, zinc chloride and aluminum chloride; metal nitrates such as calcium nitrate, barium nitrate and zinc nitrate; metal sulfates like calcium sulfate, magnesium sulfate, and aluminum sulfate; and acetic acid salts such as calcium acetate, barium acetate and zinc acetate. Most preferred are calcium chloride and calcium nitrate.
  • the coagulant solution might contain additives to improve the wetting behavior of the former.
  • the mold is removed from the bath and optionally dried.
  • the such treated mold is then immersed in the compounded latex composition according to the present invention.
  • a thin film of latex is coagulated on the surface of the mold.
  • the thickness of the thus dipped film may be influenced by the concentration of the compounded latex and/or the length of time that the salt-coated mold is in contact with the compounded latex.
  • the mold is removed from the latex composition and optionally immersed in a water bath in order to extract, for example, polar components from the composition and to wash the coagulated latex film. Thereafter, the latex coated mold is optionally dried at temperature below 80°C.
  • the latex coated mold is heat-treated at a temperature of 40 to 180°C, preferably at a temperature of 70 to 120°C in order to obtain the desired mechanical properties for the final film product. Then, the final latex film is removed from the mold.
  • the duration of the heat treatment will depend on the temperature and is typically between 1 and 60 min. The higher the temperature, the shorter is the required treatment time.
  • the compounded latex composition can be matured for at least 3 h, preferably from 24 to 48 h, after providing the compounded latex composition of the present invention and prior to immersing the treated mold in the compounded latex composition according to the present invention.
  • the final heat-treated elastomeric film may have a tensile strength of at least about 7 MPa and an elongation at break of at least about 300 %, preferably a tensile strength of at least about 10 MPa, an elongation at break of at least about 350 %, more preferred a tensile strength of at least about 15 MPa and an elongation at break of at least about 400 % and even more preferred a tensile strength of at least about 20 MPa and an elongation at break of at least about 500 %.
  • These mechanical properties may be measured according ASTM D 6319.
  • a suitable range for the stress retention is 35 to 90 %, preferably 50 to 80%.
  • the dip-molding process of the present invention can be used for any latex article that can be produced by a dip-molding process known in the art.
  • the present invention further relates to an elastomeric film made from the latex composition according to the present invention or obtained by the method according to the present invention for preparing a polymer latex composition or the compounded latex composition according to the present invention.
  • the present invention also relates to an article comprising the elastomeric film according to the present invention.
  • the article may be selected from health care devices formed from elastomeric films or including elastomeric films, surgical gloves, examination gloves, condoms, catheters, industrial gloves, textile-supported gloves and household gloves, preferably surgical gloves.
  • elastomeric films made from polymer latex compositions comprising the polymer latex of the present invention and an oxirane functional compound can by repaired and recycled.
  • the present invention also relates to a method for repairing an elastomeric film made from the polymer latex composition of the present invention by a) providing an elastomeric film made from the polymer latex composition of the present invention that is damaged or an article comprising such a damaged elastomeric film, the damaged elastomeric film having at least surfaces to be reconnected, b) re-joining the surfaces of the damaged film, c) heating or annealing the damaged elastomeric film while maintaining intimate contact of the rejoined surfaces of the damaged film at a temperature of 40°C to 200°C.
  • Items formed from an elastomeric film may be collected and sorted and optionally sterilized for handling purposes.
  • the items where there is damage, but not to the extent that they cannot be re-used, may be separated and the surface where there is damage is optionally further cleaned. This cleansing may be by washing with hydrogen peroxide or other sterilizing fluid or by passing under a carbon dioxide air stream or UV light to make sure there are no pathogens present.
  • the surfaces of the damaged film that have separated from one another may be brought together such that they contact one another, for example if there is a hole the edges of the hole are brought into contact and the surface may be heated so that the elastomeric film can soften and the surfaces seal together to repair the damage after which the surface is allowed to cool and reveal a repaired or self-healed surface.
  • the heating may be carried out where pressure is applied to the contacting areas of the damaged surface.
  • the present invention also relates to a method for recycling an elastomeric film made from the polymer latex composition of the present invention or an article comprising such an elastomeric film by cutting, shredding or comminuting said elastomeric film or article to form particles of the elastomer, optionally blending the obtained particles with particles of virgin elastomer, and forming a recycled film or article by subjecting the particles to a pressure of 1 - 20 MPa and a temperature of 40°C to 200°C.
  • Elastomeric materials such as gloves may be collected and if necessary, they can be sorted so that the nitrile containing materials are collected together while the other material is discarded or sent to alternative recycling or reprocessing facilities.
  • the collected material can be then washed and decontaminated if necessary, much like is done for the repairi ng/self-healing process.
  • the material can then be comminuted into particle sizes of not more than 2 mm average diameter, preferably not more than 1 mm average diameter and ideally of diameters in the range of 0.15 to 0.75 mm, more preferably 0.2 to 0.3 mm average diameter of the particle size.
  • the comminution or grinding process may be carried out at less than room temperature or indeed under cryogenic conditions to enable facile processing and to keep the material as particles before processing further.
  • the cool conditions avoid any re-joining of the particles until needed.
  • the material may be stored at room temperature, such as temperatures in the range of 20 to 25 °C, or under such conditions that avoid rejoining of the particles until required.
  • the material may be ground further before being fed to a blender where the material is blended with other materials, for example particles of virgin elastomeric material and customary processing aids and additives.
  • the material can be fed directly to a thermal processing system where the particles/crumb is hot pressed, 2-roll milled, calendered or extruded under pressure and at heated conditions i.e., more than 40 °C to allow fluidity in the material as a result of bonds within the material being broken, e.g., the bonds within beta hydroxy esters the material and at this stage the material can also be molded into the required final shape. After this the material can be cooled, optionally in molds or as part of an extrusion process to produce an end product that is formed from recycled material.
  • the present invention relates to use of the polymer latex composition according to the present invention or obtained by the method according to the present invention for preparing a polymer latex composition for the production of dip-molded articles or for coating or impregnating a substrate, preferably a textile or ceramic substrate.
  • the present invention relates to use of a polymer latex obtained by free-radical emulsion polymerization of a mixture of ethylen ically unsaturated monomers comprising at least 2.5 wt.-% of an ethylenically unsaturated acid, wherein the ethylenically unsaturated acid comprises an acid functional group; and a spacer group separating the ethylenically unsaturated group and the acid functional group by at least 4 atoms; for providing microbial resistance in a polymer latex composition for the preparation of an elastomeric film and/or in an elastomeric film made from the polymer latex composition.
  • the weight percentage is based on the total weight of the ethylenically unsaturated monomers in the monomer mixture.
  • microbial resistance refers to the prevention of growth and/or inhibition of microorganisms, preferably microorganisms selected from the group comprising at least one strain of bacteria, at least one strain of fungi, mold, yeast, algae and mixtures thereof.
  • the use of the polymer latex composition provides microbial resistance against at least one strain of bacteria, at least one strain of fungi, mold, yeast, algae and mixtures thereof in a polymer latex composition for the preparation of an elastomeric film and/or in an elastomeric film made from the polymer latex composition.
  • the at least one strain of bacteria may be selected from the group consisting of gram-negative bacteria, gram-positive bacteria and mixtures thereof.
  • Gram-positive and gram-negative bacteria are well known in the art and are described, e.g., in Biology of Microorganisms, "Brock”, Madigan MT, Martinko JM, Parker J, 1997, 8th Edition.
  • Gram-negative bacteria are characterized by two membranes (outer and inner membrane) and usually contain a high amount of lipopolysaccharide and a thin single-layer of peptidoglycan, while gram-positive bacteria contain only one membrane and usually have virtually no lipopolysaccharide, a multi-layered thick peptidoglycan and the coat contains teichoic acids.
  • the at least one strain of bacteria may be selected from the group comprising Pseudomonas sp., such as Pseudomonas aeruginosa, Pseudomonas pseudoalcaligenes, Pseudomonas putida, Pseudomonas stutzeri, Pseudomonas mendocina, Pseudomonas oleovorans subsp. Oleovorans, Pseudomonas fluorescens, and mixtures thereof; Burkholderia sp., such as Burkholderia cepacia; Escherichia spp. such as Escherichia coli; Alcaligenes sp.
  • Pseudomonas sp. such as Pseudomonas aeruginosa, Pseudomonas pseudoalcaligenes, Pseudomonas putida, Pse
  • Bacillus halodurans such as Bacillus halodurans; Salmonella sp.; Legionella; Comomonas aquatica; Brevundimonas intermedia; Rhizobium radiobacter; Spingobium yanoikuyae; Caldimonas sp.; Hydrogenophaga sp.; Alishewanella agri; Arthrobacter sp.; Chryseomicrobium amylolyticum; Microbacterium sp.; Microbacterium paraoxydans; Micrococcus luteus; Exiguobacterium aurantiacum; Klebsiella pneumoniae; Rhodococcus ruber; Proteus hauseri; Enterobacter cloacae; and mixtures thereof.
  • the at least one strain of fungi may be selected from the group comprising Saccharomyces cerevisiae; Pichia membranifaciens; Rhodotorula mucilaginosa; Fusarium sp. ; Aspergillus sp. such as Aspergillus niger, Aspergillus brasiliensis, and mixtures thereof; Penicillium sp.
  • Penicillium pinophilum such as Penicillium pinophilum, Penicillium funiculosum, and mixtures thereof; Aureobasidium pullulans; Geotrichum sp.; Acremonium sp.; Alternaria sp.; Cladosporium sp.; Mucor sp.; Rhizopus sp.; Stachybotrys sp.; Trichoderma sp.; Dematiaceae sp.; Phoma sp.; Eurotium sp.; Scopulariopsis sp.; Aureobasidium sp.; Monilia sp.; Botrytis sp.; Stemphylium sp.; Chaetomium sp.; Mycelia sp.; Neurospora sp.; Ulocladium sp.; Paecilomyces sp.; Wallemia sp.; Curvularia sp.; Vishniacozyma
  • the at least one strain of yeast may be selected from the group comprising Saccharomyces cerevisiae; Pichia membranifaciens; Rhodotorula mucilaginosa; and mixtures thereof.
  • the at least one strain of algae may be selected from the group comprising Chlorella vulgaris; Chlorella emersonii; Stichococcus bacillaris; Pleurococcus sp.; Anacystis montana; and mixtures thereof.
  • the acid functional group of the ethylenically unsaturated acid may be selected from carboxylic acid groups and phosphorous containing acid groups.
  • Suitable phosphorous containing acid groups may be selected from phosphoric acid groups and phosphonic acid groups.
  • the acid functional group of the ethylenically unsaturated acid is selected from carboxylic acid groups.
  • the ethylenically unsaturated acid comprising an acid functional group and a spacer group separating the ethylenically unsaturated group and the acid functional group by at least 4 atoms may be selected from compounds having the structure:
  • R 1 is selected from H and Ci-C 4 alkyl
  • R 2 is selected from H or - A - X;
  • A is a divalent spacer group separating the ethylenically unsaturated group and the functional group X by at least 4 atoms independently at each occurrence selected from: - (C(0) - W) n - Y - (0)m- and - (CH 2 ) k - O - (C(O)) P - Y - (O) m - wherein n, m, k and p are integers independently at each occurrence selected from 0 or 1 ; W is - O - or - NR 3 -;
  • R 3 is selected from H and Ci-C 4 alkyl
  • Y is selected from optionally substituted linear, branched, cyclic or aromatic C 2 to C 3 o divalent hydrocarbon or hetero hydrocarbon groups;
  • X is selected from - C(O)OH and - P(O)(OH) 2 , preferably - C(O)OH; with the proviso that if X is - C(O)OH m is 0; or
  • the ethylenically unsaturated acid comprising an acid functional group and a spacer group separating the ethylenically unsaturated group and the acid functional group by at least 4 atoms is selected from carboxy (C 2 -C3o)alkyl (meth)acrylates, C 7 to C15 fatty acids having a terminal ethylenically unsaturated group mono (meth)acryloyloxy alkyl esters of dicarboxylic esters and more preferred from carboxy (C2-Ci2)alkyl (meth)acrylates and omega-(meth)acryloyoloxy (C2-Ci2)alkyl succinates.
  • Suitable monomers of ethylenically unsaturated acid comprising an acid functional group and a spacer group separating the ethylenically unsaturated group and the acid functional group by at least 4 atoms are commercially available from Solvay (Belgium) as Sipomer® p-CEA, Sipomer® PAM 100, Sipomer® PAM 200, Sipomer® PAM 300, Sipomer® PAM 4000, and Sipomer® PAM 5000.
  • the amount of ethylenically unsaturated acid comprising an acid functional group and a spacer group separating the ethylenically unsaturated group and the acid functional group by at least 4 atoms is at least 2.5 wt.-%, preferably at least 2.8 wt.-%, even more preferably at least 3.0 wt.-%, most preferably at least 3.6 wt.-%, based on the total weight of the ethylenically unsaturated monomers in the monomer mixture.
  • the amount of ethylenically unsaturated acid comprising an acid functional group and a spacer group separating the ethylenically unsaturated group and the acid functional group by at least 4 atoms may be up to 10.0 wt.-%, up to 9.5 wt.-%, up to 9.0 wt.-%, up to 8.5 wt.-%, up to 8.0 wt.-%, up to 7.5 wt.-%, up to 7.0 wt.-%, up to 6.5 wt.-%, up to 6.0 wt.-%, based on the total weight of the ethylenically unsaturated monomers in the monomer mixture.
  • the amount of ethylenically unsaturated acid comprising an acid functional group and a spacer group separating the ethylenically unsaturated group and the acid functional group by at least 4 atoms may be in a range of from 2.5 to 10.0 wt.-%, preferably from 3.0 to 10.0 wt.-%, more preferably from 3.6 to 10.0 wt.-%, even more preferably from 3.6 to 8.0 wt.-%, most preferably from 3.6 to 6.0 wt.-%, based on the total weight of the ethylenically unsaturated monomers in the monomer mixture.
  • the present invention relates to use of at least 2.5 wt.-% of an ethylenically unsaturated acid in a mixture of ethylenically unsaturated monomers in the preparation of a polymer latex by free-radical emulsion polymerization of a mixture of ethylenically unsaturated monomers; wherein the ethylenically unsaturated acid comprises an acid functional group; and a spacer group separating the ethylenically unsaturated group and the acid functional group by at least 4 atoms; for providing microbial resistance in a polymer latex composition for the preparation of an elastomeric film and/or in an elastomeric film made from the polymer latex composition.
  • the weight percentage is based on the total weight of the ethylenically unsaturated monomers in the monomer mixture.
  • the ethylenically unsaturated acid comprising an acid functional group and a spacer group separating the ethylenically unsaturated group and the acid functional group by at least 4 atoms as well as the weight percentages may be as described above.
  • the polymer latex composition and/or the elastomeric film made from the polymer latex composition according to the present invention is effective against microorganism and provides microbial resistance without the use of conventional biocides.
  • Figure 1 Model density charts for bacteria, yeast and fungi in dip slides.
  • Figure 2 Bacterial efficacy on the surface of medical examination gloves (Examples 1 a, 2a, 6a to 8a) - Log reduction from challenge inoculum.
  • TSC total solid content
  • MAA methacrylic acid
  • BCEA 2-carboxyethyl acrylate oligomer (Sipomer® p-CEA)
  • tDDM tert-dodecyl mercaptan
  • Na 4 EDTA tetra sodium salt of ethylenediaminetetraacetic acid
  • ZDEC zinc diethyldithiocarbamate
  • the dispersions were characterized by determination of TSC, pH value, viscosity (Brookfield LVT) and z-average particle size. Furthermore, the final films were tested for bioburden levels, challenge tests and bactericidal efficacy.
  • the pH value was determined according to DIN ISO 976. After applying a 2-point calibration using buffer solutions, the electrode of a Schott CG 840 pH meter was immersed in the dispersion at 23°C and the constant value on the display was recorded as the pH value.
  • the latex viscosity was determined at 23°C using a Brookfield LVT viscometer. Approximately 220 ml of the liquid (freed of air bubbles) was filled into a 250 ml beaker and the spindle of the viscometer was immersed up to the mark on the spindle. The viscometer was then switched-on and after approximately 1 minute the value was recorded until it was constant. The viscosity range determines the choice of spindle and rotational speed and the factor for the recorded value to calculate the viscosity. Determination of the particle size (PS):
  • the z-average particle size was measured using a Malvern Zetasizer Nano S (ZEN 1600) using dynamic light scattering.
  • the latex sample was diluted with deionized water to the turbidity level described in the manual and transferred in the test cuvette.
  • the cuvette was gently mixed to make the sample homogenous and the cuvette was placed in the measurement device. The value was recorded as software generated z-average particle size.
  • Nitrile latex with compounding materials at the desired pH value was stirred for 24 h unless specified in individual examples below, at room temperature, and then coagulant dipped as follows.
  • a ceramic spade was washed with soap and then thoroughly rinsed with deionized water before drying in an air-circulating oven set at 65-70°C (spade temperature, 55-60°C) until dry.
  • a solution of coagulant was prepared by dissolving calcium nitrate (18 % wt.) and calcium carbonate (2% wt.) in deionized water.
  • the dry spade was then dipped into the salt solution, removed and then dried in an air-circulating oven set at 70-75°C (spade temperature, 60-65°C) until dry.
  • the salt-coated spade was then dipped into the desired, compounded latex (which has total solid content of 18 wt.-% and matured for 24 hours at room temperature after compounding) for a dwell time of 5 seconds, before removing it and placing the latex-coated spade into an air circulating oven, set at 100°C for 1 min, to gel the film.
  • the thus gelled film was then washed in a tank of deionized water set to 50-60°C for 1 min, before curing in an air-circulating oven set to 120°C for 20 min; after which, the thus cured/vulcanized film was cooled, and removed from the spade before aging for 22 h in an air-circulating oven set to 100°C.
  • This method gives a total count of microorganisms, and the selective detection of yeasts and molds in latex or fluids using dip slide.
  • glassware Prior to sample preparation, glassware must be cleaned, sterilize and dried at 70°C.
  • the dip slide tube to screw cap to be remove and dip into the fluid for 5 sec.
  • the dip slide can be either dipped or used by pouring the liquid to be tested onto the agar surface, in case of small sample quantities. The dip slide into the tube was removed and closes tightly.
  • Each dip slide tubes were labeled with sample type, sample source, dilution factor (if any), test date and any other necessary information to ensure trace ability. Incubation of dip slide is to be performed at 30°C for 5 days.
  • the level of the microorganisms, yeasts and molds was observed and recorded on the dip slide pad for the first 24 h, then the incubation was continued. After the incubation period, various results can be observed on the pad and the density of the colonies growth should be interpreted according to the model density charts.
  • the bacterial count/ml of the sample is determined by comparing the density of the colonies appearing on the slide with densities shown on the model chart. Growth appearing on the slide may consist either purely of fungi or yeasts or may be caused by both fungi and yeasts forming mixed growth. Fungi give rise to soft and fluffy colonies, while yeast colonies are usually ball shaped and slightly puffed up. Sometimes they are flat and dry. Comparison of yeast growth with the model chart is carried out as with bacteria.
  • GAM Global Analytical Method
  • HPLC High performance liquid chromatography
  • sample Wt 2 g ( ⁇ 0.05 g) of the sample was weighted into a 21 mL vial and the weight was recorded (“Sample Wt”). 10 mL of GAM 11 method reagent was added and the total weight was recorded (“Final Wt”), cap was closed and vigorously shaken using the shaker for 30 min. The sample was centrifuged at 14,500rpm for 15 min to obtain a clear supernatant. The supernatant was filtered through a 0.45 pm syringe filter into a vial and analyzed by HPLC. A blank containing only the GAM 11 method reagent was measured additionally.
  • the principle of this test is to access the microbial growth after incubation at an appropriate temperature and time.
  • the growth media appropriate to the test organisms are inoculated with known aliquots of each sample.
  • the test involved a bioburden analysis and was carried out using serial dilutions in triplicate plated out on agar plates (nutrient agar incubated at 30°C for 2 days for enumeration of bacteria and on malt extract agar incubated at 25°C for 5 days for enumeration of yeasts and molds).
  • a serial dilution of the test sample in MRD (Maximum Recovery Diluent) under aseptic conditions was prepared.
  • the center of the plate was inoculated with 0.1 mL of the sample or serial dilution of the sample (or 0.1 g if the sample is viscous and difficult to dispense) and spread using a sterile spreader.
  • the petri dishes were inverted and incubated in an incubator at the appropriate temperature (25°C for fungi and 30°C for bacteria). The plates were removed and inspected for growth after 48 h incubation for bacteria and 120 h incubation for fungi.
  • the differentiation of yeast and mold colonies is a matter of experience, but yeasts generally form circular, smooth colonies, whereas molds form irregular, rhizoid colonies. If in doubt, it was confirmed by microscopic identification.
  • a biocide efficacy or challenge test is a procedure in which a product is challenged by exposure to specified types of bacteria and fungi to determine whether it is adequately preserved. Each sample was challenged with a pool of bacterial or fungal strains at high concentration.
  • Test organisms should be representative of those likely to occur as contaminants during use and should consist of Gram-positive and Gram-negative bacteria, moulds and yeasts. Wild type isolates obtained as a result of contamination of earlier batches of a product may also be included. The organisms were inoculated into samples of the product and aliquots removed at appropriate intervals (usually weekly) for the determination of survivors. Measured volumes of the sample were removed, and viable organisms enumerated. At weekly intervals the samples were re-challenged.
  • the data generated was used to determine the threshold concentration of biocide required to protect a product against microbial spoilage.
  • the repeated inoculation study was a good simulation of the type of repeated exposure products may be subjected to during manufacturing, shipping, and use and may be used to predict the preservative’s performance under end-use conditions.
  • Table 1 Standard bacterial and fungal strains
  • Table 2 Wild type bacterial and fungal strains isolated from infected Synthomer products
  • Method (A) a saline or buffered saline solution
  • Method (B) a saline or buffered saline solution containing an organic load.
  • Each method represents a different means of microbial contamination that can be expected in the healthcare environment.
  • Results of the test methods described in this document are limited to bactericidal efficacy against vegetative bacteria.
  • the tests for the current invention involved Method (A) in the main.
  • Challenge bacteria should be American Type Culture Collection (ATCC) strains. To ensure vital bacteria that are not far removed from wild type characteristics, bacteria utilized in any phase of these studies should be no more than five passages from the original stock received. Challenge bacteria which used in this study were:
  • test preparation with a surface area of 1cm 2 was cut from the glove.
  • the specimen with the required surface area may be prepared by cutting a circular with a punch die.
  • the inoculum was prepared by inoculating an agar plate with a pure culture of the appropriate challenge organism utilizing a standard streak isolation technique. A plate was incubated at appropriate temperature for 18 to 24 h. 3-5 isolated colonies with identical colony morphology were selected, the colonies were transferred into a tube containing 5 mL of sterile saline solution. The suspension was adjusted to match a 0.5 McFarland turbidity standard.
  • the Challenge Delivery Option involved the following - 20pL aliquot of the prepared challenged inoculums was placed on the sterile cover slip. With the forceps, the edge of the test specimen was rested on the surface of the challenged bacteria. All the samples were evaluated at contact times: 0, 5, 10, 15, 20, 25 and 30 min. When the specified contact time was completed, the specimen was immediately removed from the cover slip with forceps and the specimen was placed into a centrifuge tube containing 10 ml of sodium thiosulphate solution (neutralizer solution) and mixed for 15 s using a vortex mixer. The number of recovered bacteria in duplicate was determined by standard plate count method. All the data was in the form of colony forming unit (CFU).
  • CFU colony forming unit
  • TS CFU extracted from antibacterial treated test specimen.
  • Log Reductions convey how effective a product is at reducing pathogens. The greater the log reduction the more effective the product is at killing bacteria and other pathogens that can cause infections.
  • a log reduction takes the power in the opposite direction. For example, a log reduction of
  • example log reduction of 3 is a 99.9% reduction compared with a log reduction of 6 which is equivalent to a 99.9999% reduction.
  • Example 1 The pH was adjusted using potassium hydroxide (5 % aqueous solution) to pH 7.5 and the residual monomers were removed by vacuum distillation at 60° C. 0.5 parts by weight of a Wingstay L type antioxidant (60% dispersion in water) was added to the raw latex, and the pH was adjusted to 8.2 by addition of a 5 % aqueous solution of potassium hydroxide. 0.05 parts by weight of BIT and 0.04 parts by weight of formaldehyde were used as biocides for standard preservation. The following characterization results were obtained for Example 1 :
  • Viscosity 30.5mPas (1/60);
  • a dry, salt-coated spade was dipped into the diluted compounded latex solution with 18 % TSC comprising of 0.8 phr S, 0.7 phr ZDEC, 1 phr ZnO and titanium dioxide at pH 10 with a dwell time of 5 seconds before the film was gelled at 100°C for 1 minute, washed with deionized water for 1 minute (in a tank set at 50-60 °C), followed by drying and curing/vulcanization in an air-circulating oven set at 120°C for 20 min, to ensure complete drying and crosslink formation.
  • Example 1 This was an exact repeat of Example 1 but without biocide, under preparation of dip-coated film similar to Example 1 a.
  • Example 3 1.2 wt.-% of BCEA
  • composition was prepared in the same manner as in Example 1 except that 4.8 parts methacrylic acid was used and 1.2 part of Sipomer® p-CEA a mixture of 2-carboxyethyl acrylate oligomers commercially available as from Solvay (Belgium) was used but without biocide. The pH was adjusted to 7.1 .
  • Example 4 2.4 wt.-% of BCEA
  • composition was prepared in the same manner as in Example 1 except that 3.6 parts methacrylic acid was used and 2.4 part of BCEA was used but without biocide. The pH was adjusted to 7.1.
  • Example 6 6.0 wt.-% of BCEA
  • composition was prepared in the same manner as in Example 1 except that no methacrylic acid was used and 6 part of BCEA was used but without biocide.
  • Tg -22°C
  • Viscosity 22.5mPas (1/60);
  • Particle size, P z 127nm.
  • Example 6a Preparation of dip-coated film (6.0 wt.-% of BCEA)
  • Example 7 6.0 wt.-% of 2-acryloyloxyethyl succinate
  • composition was prepared in the same manner as in Example 1 except that no methacrylic acid was used and 6 part of 2-acryloyloxyethyl succinate was used but without biocide.
  • the pH was adjusted to 7.1 .
  • Example 7a Preparation of dip-coated film (6.0 wt.-% of 2-acryloyloxyethyl succinate)
  • Example 8 6.0 wt.-% of 2-methacryloyloxyethyl succinate
  • composition was prepared in the same manner as in Example 1 except that no methacrylic acid was used and 6 part of 2-methacryloyloxyethyl succinate was used but without biocide.
  • the pH was adjusted to 7.1 .
  • Example 8a Preparation of dip-coated film (6.0 wt.-% of 2-methacryloyloxyethyl succinate)
  • Example 1 with biocide were found to pass the bio-sterility results after 9 months.
  • Example 2 without biocide Example 3 with 1 .2 parts, and Example 4 with 2.4 parts of BCEA failed the bio-sterility test and infection was observed.
  • Example 5 with 3.6 parts of BCEA Example 6 with 6 parts of BCEA, Example 7 with 6 parts of 2-acryloyloxyethyl succinate and Example 8 with 6 parts of 2-methacryloyloxyethyl succinate, have passed the biosterility test without any contamination.
  • Example 1 -2 Screening for Microbial Infection Example 1 -2 were found to be sterile on receipt, Example 2 was heavily infected with bacteria. This Example was disinfected by overnight incubation with 350 ppm hydrogen peroxide. All four uninoculated samples were free from infection after 6 weeks storage at room temperature.
  • Example 6 is not prone to microbial infection and remains infection-free even after 6 months from production without the addition of biocides.
  • Example 2 (unpreserved control) was used as a control to test for the effectiveness of bacterial and fungal inocula used in the experiment. This sample failed all rounds of bacterial and fungal challenge, thus confirming the potencies of the inocula (Tables 5 and 6).
  • Example 1 The sample with standard preservation (Example 1) withstood the first bacterial challenge but became infected after the second bacterial challenge (Table 5). The infection persisted following subsequent challenges and was still present 2 weeks after the last challenge. Apart from the no biocide control, all the test samples passed all four fungal challenge tests (Table 6).
  • Table 6 Yeast and mould growths rating 7 days after inoculation
  • Examples 6a to 8a show better bacterial efficacy than Example 2a (without biocide) and comparable or better bacterial efficacy than Example 1 (with biocide).
  • Example 7a shows prominent bacterial efficacy on gram positive bacteria.
  • Examples 6a to 8a show better % bacterial efficacy compared to Example 2a (without biocide).
  • Example 6a shows 2x of reduction efficacy compared to Example 1 (with biocide).
  • Example 7a shows prominent bacterial efficacy on gram positive bacteria.

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Abstract

The present invention relates to a polymer latex for the preparation of an elastomeric film, to such elastomeric films and articles comprising said elastomeric films, to latex compositions comprising said polymer latex and to methods for making articles using said film, e.g., dip-molded articles.

Description

POLYMER LATEX FOR THE PREPARATION OF AN ELASTOMERIC FILM HAVING MICROBIAL RESISTANCE
The present invention relates to a polymer latex for the preparation of an elastomeric film, to such elastomeric films and articles comprising said elastomeric films, to latex compositions comprising said polymer latex and to methods for making articles using said film, e.g., dip-molded articles.
Background of the invention
Medical gloves are used during medical examination and procedures that help prevent the spread of infections. Medical gloves are used to prevent the transfer of infection between the medical workers and their patients. It is important that medical gloves are sterile, i.e., are free of microbiological contamination including bacteria, fungi and yeast. Sterile gloves are required for all surgical procedures and other medical purposes involving greater risk and danger of infection. Sterile examination gloves are available in individual packages, but the gloves remain sterile only until the package is opened, after which they can carry infections. In addition, bio-microbial infection of the polymer latex composition during production of the medical gloves may occur, resulting in microbial-infected medical gloves. Typically, biocides are used to prevent microbial infection of the polymer latex composition and the gloves.
WO 2017/148957 A1 relates to medical examination gloves comprising natural or nitrile rubber latex, and a water-soluble singlet oxygen generator.
It is one object of the present invention to provide polymer latex composition that provide microbial resistance, especially for bacteria, fungi, mold, algae, and yeast, in the polymer latex composition and the resulting article therefrom, without the use of any biocide.
Another object is to provide a polymer latex composition suitable for producing medical gloves such as examination and/or surgical gloves. Surgical gloves must have good stress retention properties and superior softness. Poor stress retention leads to poor fitting of the glove to the forearm part of a surgeon resulting possibly in cross-contamination.
Accordingly, another object of the present invention is to provide a polymer latex that gives elastomeric films that have excellent stress retention properties and superior softness and such polymer latex can be used in a range of articles but in particular they are suitable for use in surgical glove as well as condom applications. Frequently natural latex surgical gloves are employed. But natural rubber may cause protein allergy issues. Other polymers such as polyisoprene or polychloroprene are also used for making surgical gloves. However, the processing costs for these materials are very high and the production is not environmental-friendly. Therefore, another object of the present invention, is to provide a polymer latex composition, which is allergy and environmentally-friendly.
Summary of the invention
The following clauses summarize some aspects of the present invention.
According to a first aspect, the present invention relates to a polymer latex composition for the preparation of an elastomeric film comprising a polymer latex obtainable by free-radical emulsion polymerization of a mixture of ethylenically unsaturated monomers comprising: (a) 15 to 99 wt.-% of conjugated dienes; (b) 0 to 80 wt.-% of ethylenically unsaturated nitrile monomers; (c) 0 to 70 wt.-% of vinyl aromatic monomers; the sum of ethylenically unsaturated nitrile monomers (b) and vinyl aromatic monomers (c) being 0.95 to 84.95 wt.- %; (d) 2.5 to 10.0 wt.-% of an ethylenically unsaturated acid comprising an acid functional group, and a spacer group separating the ethylenically unsaturated group and the acid functional group by at least 4 atoms; and (e) 0 to 65 wt.-% of co-polymerizable ethylenically unsaturated compounds; wherein monomers (a) to (e) are different from each other and the weight percentages being based on the total weight of the ethylenically unsaturated monomers in the monomer mixture; and wherein the pH of the polymer latex composition is lower than 7.5.
The acid functional group of the ethylenically unsaturated acid (d) may be selected from carboxylic acid groups and phosphorous containing acid groups, preferably carboxylic acid groups.
The ethylenically unsaturated acid (d) may be selected from compounds having the structure:
CHR2=CR1 - A - X, wherein R1 is selected from H and C1-C4 alkyl; R2 is selected from H or - A - X; A is a divalent spacer group separating the ethylenically unsaturated group and the functional group X by at least 4 atoms independently at each occurrence selected from: - (C(O) - W)n- Y - (O)m-; - (C(O) - W)n- Y - O- C(O) - Y - and
- (CH2)k - O - (C(O))P — Y - (O)m-; n, m, k and p are integers independently at each occurrence selected from 0 or 1 ; W is - O - or - NR3 -; R3 is selected from H and C1-C4 alkyl; Y is independently at each occurrence selected from optionally substituted linear, branched, cyclic or aromatic C2 to C3o divalent hydrocarbon or hetero hydrocarbon groups; X is selected from - C(O)OH and - P(O)(OH)2; with the proviso that if X is - C(O)OH m is 0; or- A - X is selected from - C(O) - O - (Y -C(O) - O)i - H, wherein I is an integer from 2 to 10, preferably from 2 to 7; and mixtures thereof.
The ethylenically unsaturated acid (d) may be selected from carboxy (C2-C3o)alkyl (meth)acrylates, C? to C15 fatty acids having a terminal ethylenically unsaturated group and mono (meth)acryloyloxy alkyl esters of dicarboxylic esters and preferably from carboxy (C2- Ci2)alkyl (meth)acrylates and omega-(meth)acryloyloxy (C2-Ci2)alkyl succinates and more preferred from 2-(meth)acryloyloxyethyl succinate, 2-carboxyethyl acrylate and oligomers thereof having the structure CH2=CH-C(O)-O-(C2H4-C(O) -O)i-H with I being an integer from 2 to 7 and mixtures thereof.
The ethylenically unsaturated acid (d) may be present from 3.0 to 8.5 wt.-%, preferably from 3.4 to 8.0 wt.-%, more preferably from 3.6 to 7.0 wt.-%, even more preferably 3.6 to 6.5 wt.-%, most preferably from 3.6 to 6.0 wt.-%, based on the total weight of the ethylenically unsaturated monomers in the monomer mixture.
The mixture of ethylenically unsaturated monomers for the preparation of an elastomeric film comprising a polymer latex obtainable by free-radical emulsion polymerization may further comprise (f) up to 10.0 wt.-%, preferably in a range of from 0 to 7.0 wt.-%, more preferably in a range of 0 to 3.5 wt.-% of an ethylenically unsaturated acid being different from (d), based on the total weight of the ethylenically unsaturated monomers in the monomer mixture.
The ethylenically unsaturated acid (d) and the ethylenically unsaturated acid (f) may be present in an amount in the range of up to 10.0 wt.-%, preferably in the range of up to 8.0 wt.-%, more preferably in a range of up to 6.0 wt.-%, based on the total weight of the ethylenically unsaturated monomers in the monomer mixture.
The ethylenically unsaturated acid (f) may be selected from
- ethylenically unsaturated carboxylic acids and salts thereof, preferably selected from (meth)acrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, and salts thereof;
- ethylenically unsaturated polycarboxylic acid anhydride, preferably selected from maleic anhydride, methacrylic anhydride, cis-cyclohexene-1 ,2-dicarboxylic anhydride, and dimethylmaleic anhydride, bromomaleic anhydride, 2,3-dichloromaleic anhydride, citraconic anhydride, crotonic anhydride, itaconic anhydride, (2-dodecen-1 -yl) succinic anhydride;
- polycarboxylic acid partial ester monomers and salts thereof, preferably selected from monomethyl maleate, monomethyl fumarate, monoethyl maleate, monoethyl fumarate, monopropyl maleate, monopropyl fumarate, monobutyl maleate, monobutyl fumarate, mono(2-ethyl hexyl) maleate, mono(2-ethyl hexyl) fumarate; and combinations thereof.
It is envisaged that
(a) the conjugated dienes are selected from butadiene, isoprene, 2,3-dimethyl-1 ,3- butadiene, 2-ethyl-1 ,3-butadiene, 1 ,3-pentadiene, myrcene, ocimene, farnasene and combinations thereof;
(b) the ethylenically unsaturated nitrile monomers are selected from (meth)acrylonitrile, alpha-cyanoethyl acrylonitrile, fumaronitrile, alpha-chloronitrile and combinations thereof;
(c) the vinyl aromatic monomers are selected from styrene, alpha-methyl styrene, vinyl toluene and combinations thereof; and
(e) the co-polymerizable ethylenically unsaturated compounds are selected from (e1 ) alkyl esters of ethylenically unsaturated acids, preferably selected from methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, iso-propyl (meth)acylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate and combinations thereof;
(e2) hydroxyalkyl esters of ethylenically unsaturated acids, preferably selected from 2-hydroxy ethyl(meth)acrylate;
(e3) amides of ethylenically unsaturated acids, preferably selected from (meth)acryl amide N-methylol amide groups and combinations thereof;
(e4) vinyl carboxylates, preferably vinyl acetate;
(e5) alkoxyalkyl esters of ethylenically unsaturated acids, preferably selected from ethoxyethyl acrylate, methoxyethyl acrylate and combinations thereof;
(e6) monomers having at least two ethylenically unsaturated groups, preferably selected from divinyl benzene, ethylene glycol dimethacrylate, 1 ,4 butanediol di(meth)acrylate and combinations thereof;
(e7) ethylenically unsaturated silanes; and combinations thereof.
The mixture of ethylenically unsaturated monomers for the polymer latex may comprise:
(a) 20 to 98 wt.-% of conjugated dienes, preferably selected from butadiene, isoprene and combinations thereof, more preferred butadiene;
(b) 1 to 60 wt.-% of ethylenically unsaturated nitrile monomers, preferably acrylonitrile;
(c) 0 to 40 wt.-% of vinyl aromatic monomers, preferably styrene; (d) 3.0 to 10.0 wt.-% of ethylenically unsaturated acids comprising an acid functional group, and a spacer group separating the ethylenically unsaturated group and the acid functional group by at least 4 atoms, preferably selected from 2-(meth)acryloyloxyethyl succinate, 2-carboxyethyl acrylate and oligomers thereof having the structure CH2=CH- C(O)-O-(C2H4-C(O) — O)I— H with I being an integer from 2 to 7;
(e1 ) 0 to 25 wt.-% of Ci to Cs alkyl (meth)acrylates;
(e3) 0 to 10 wt.-% of amides of ethylenically unsaturated acids;
(e4) 0 to 10 wt.-% of vinyl esters;
(e7) 0 to 10 wt.-% of ethylenically unsaturated silanes;
(f) 0 to 10.0 wt.-% of ethylenically unsaturated acids different from (d) ; the weight percentages being based on the total weight of the ethylenically unsaturated monomers in the monomer mixture.
The polymer latex composition may be completely free of a biocide.
The pH of the polymer latex composition may be in the range of 6.0 to less than 7.5, preferably of 6.5 to 7.2.
The polymer latex composition may further comprise an oxirane functional compound.
According to a further aspect, the invention relates to a method for preparing a polymer latex composition comprising: preparing a polymer latex by free-radical emulsion polymerization of a mixture of ethylenically unsaturated monomers comprising:
(a) 15 to 99 wt.-% of conjugated dienes;
(b) 0 to 80 wt.-% of ethylenically unsaturated nitrile monomers;
(c) 0 to 70 wt.-% of vinyl aromatic monomers; the sum of ethylenically unsaturated nitrile monomers (b) and vinyl aromatic monomers (c) being 0.95 to 84.95 wt.-%;
(d) 2.5 to 10.0 wt.-% of an ethylenically unsaturated acid comprising: an acid functional group; and a spacer group separating the ethylenically unsaturated group and the acid functional group by at least 4 atoms;
(e) 0 to 65 wt.-% of co-polymerizable ethylenically unsaturated compounds; and
(f) 0 to 10.0 wt.-%, of an ethylenically unsaturated acid being different from (d); wherein monomers (a) to (f) are different from each other and the weight percentages being based on the total weight of the ethylenically unsaturated monomers in the monomer mixture; and adjusting the pH of the polymer latex composition to be lower than 7.5. Another aspect of the present invention relates to use of the polymer latex composition as discussed or obtained by the method as discussed for the production of dip-molded articles or for coating or impregnating a substrate, preferably a textile or ceramic substrate.
In addition, according to a further aspect of the present invention, the invention relates to a compounded latex composition suitable for the production of dip-molded articles comprising the polymer latex composition as discussed or obtained by the method as discussed, and optionally adjuvants selected from sulfur vulcanization agents, accelerators for sulfur vulcanization, crosslinkers, polyvalent cations and combinations thereof.
The monomer mixture to obtain the polymer latex for the compounded polymer latex composition may further comprise an ethylenically unsaturated acid (f).
The compounded latex composition may comprise 0 to 2.8 wt.-%, preferably 0.5 to 2.8 wt.- %, more preferred 1 .0 to 2.0 wt.-%, most preferred 1 .5 to 2.0 wt.-% sulfur and 0 to 2.8 wt.- %, preferably 1 .0 to 2.0 wt.-%, more preferred 1 .2 to 1 .8 wt.-% of sulfur vulcanization agents and 0.5 wt.-% to 2.5 wt.-% of ZnO, the weight percentages being based on solid latex polymer.
Another aspect of the present invention relates to a method for making dip-molded articles by a) providing a compounded latex composition as described; b) immersing a mold having the desired shape of the final article in a coagulant bath comprising a solution of a metal salt; c) removing the mold from the coagulant bath and optionally drying the mold; d) immersing the mold as treated in step b) and c) in the compounded latex composition of step a); e) coagulating a latex film on the surface of the mold; f) removing the latex-coated mold from the compounded latex composition and optionally immersing the latex-coated mold in a water bath; g) optionally drying the latex-coated mold; h) heat treating the latex-coated mold obtained from step e) or f) at a temperature of 40°C to 180°C, preferably 70°C to 120°C; and
I) removing the latex article from the mold.
After step a) and prior to step d) the compounded latex composition may be matured for at least 3 hrs, preferably from 24 to 48 hrs. Furthermore, another aspect of the present invention relates to an elastomeric film made from the polymer latex composition as described or obtained by the method for preparing a polymer latex composition as described or the compounded latex composition as described.
Another aspect of the present invention relates to an article comprising the elastomeric film as described.
The article may be selected from surgical gloves, examination gloves, condoms, catheters, industrial gloves, textile-supported gloves and household gloves, preferably surgical gloves.
A further aspect of the present invention relates to a method for repairing an elastomeric film as described or an article as described by a) providing elastomeric film as described that is damaged or an article as described comprising a damaged elastomeric film, the damaged elastomeric film having at least surfaces to be reconnected; b) re-joining the surfaces of the damaged film; c) heating or annealing the damaged elastomeric film while maintaining intimate contact of the rejoined surfaces of the damaged film at a temperature of 40°C to 200°C.
Another aspect of the present invention relates to a method for recycling an elastomeric film as described or an article as described comprising an elastomeric film by cutting, shredding or comminuting said elastomeric film or article to form particles of the elastomer, optionally blending the obtained particles with particles of virgin elastomer, and forming a recycled film or article by subjecting the particles to a pressure of 1 - 20 MPa and a temperature of 40°C to 200°C.
In addition, according to a further aspect of the present invention, the invention relates to use of a polymer latex obtained by free-radical emulsion polymerization of a mixture of ethylenically unsaturated monomers comprising at least 2.5 wt.% of an ethylenically unsaturated acid, the weight percentage being based on the total weight of the ethylenically unsaturated monomers in the monomer mixture, wherein the ethylenically unsaturated acid comprises an acid functional group; and a spacer group separating the ethylenically unsaturated group and the acid functional group by at least 4 atoms; for providing microbial resistance in a polymer latex composition for the preparation of an elastomeric film and/or in an elastomeric film made from the polymer latex composition. The ethylenically unsaturated acid may be selected from 2-(meth)acryloyloxyethyl succinate, 2-carboxyethyl acrylate and oligomers thereof having the structure CH2=CH- C(O)-O-(C2H4-C(O) — O)I— H with I being an integer from 2 to 7 and mixtures thereof, preferably from 2-carboxyethyl acrylate and oligomers thereof having the structure CH2=CH-C(O)-O-(C2H4-C(O) -O)I-H with I being an integer from 2 to 7.
Another aspect of the present invention relates to use of at least 2.5 wt.% of an ethylenically unsaturated acid in a mixture of ethylenically unsaturated monomers in the preparation of a polymer latex by free-radical emulsion polymerization of a mixture of ethylenically unsaturated monomers, the weight percentage being based on the total weight of the ethylenically unsaturated monomers in the monomer mixture; wherein the ethylenically unsaturated acid comprises an acid functional group; and a spacer group separating the ethylenically unsaturated group and the acid functional group by at least 4 atoms; for providing microbial resistance in a polymer latex composition for the preparation of an elastomeric film and/or in an elastomeric film made from the polymer latex composition.
The ethylenically unsaturated acid may be selected from 2-(meth)acryloyloxyethyl succinate, 2-carboxyethyl acrylate and oligomers thereof having the structure CH2=CH- C(O)-O-(C2H4-C(O) — O)I— H with I being an integer from 2 to 7 and mixtures thereof, preferably from 2-carboxyethyl acrylate and oligomers thereof having the structure CH2=CH-C(O)-O-(C2H4-C(O) -O)I-H with I being an integer from 2 to 7.
Detailed description of the invention:
The polymer latex composition according to one aspect of the present invention for the preparation of an elastomeric film comprises a polymer latex, which is obtainable by free- radical emulsion polymerization of a mixture of ethylenically unsaturated monomers comprising:
(a) 15 to 99 wt.-% of conjugated dienes;
(b) 0 to 80 wt.-% of ethylenically unsaturated nitrile monomers;
(c) 0 to 70 wt.-% of vinyl aromatic monomers; the sum of ethylenically unsaturated nitrile monomers (b) and vinyl aromatic monomers (c) being 0.95 to 84.95 wt.-%;
(d) 2.5 to 10.0 wt.-% of an ethylenically unsaturated acid comprising an acid functional group; and a spacer group separating the ethylenically unsaturated group and the acid functional group by at least 4 atoms; and (e) 0 to 65 wt.-% of co-polymerizable ethylenically unsaturated compounds, wherein monomers (a) to (e) are different from each other and the weight percentages being based on the total weight of the ethylenically unsaturated monomers in the monomer mixture; and wherein the pH of the polymer latex composition is lower than 7.5.
Conjugated diene monomers (a) suitable for the preparation of the polymer latex according to the present invention may include conjugated diene monomers, selected from 1 ,3- butadiene, isoprene, 2,3-dimethyl-1 ,3-butadiene, 2-chloro-1 ,3-butadiene, 1 ,3-pentadiene,
1 .3-hexadiene, 2,4-hexadiene, 1 ,3-octadiene, 2-methyl-1 ,3-pentadiene, 2, 3-dimethyl-1 ,3- pentadiene, 3,4-dimethyl-1 ,3-hexadiene, 2, 3-diethyl-1 ,3-butadiene, 4, 5-diethyl-1 ,3- octadiene, 3-butyl-1 ,3-octadiene, 3,7-dimethyl-1 ,3,6-octatriene, 2-methyl-6-methylene-1 ,7- octadiene, 7-methyl-3-methylene-1 ,6-octadiene, 1 ,3,7-octatriene, 2-ethyl-1 ,3-butadiene, 2- amyl-1 ,3-butadiene, 3,7-dimethyl-1 ,3,7- octatriene, 3, 7-dimethyl-1 ,3,6-octatriene, 3,7,11 - trimethyl-1 ,3,6,10-dodecatetraene, 7,1 1 -dimethyl-3-methylene-1 ,6,10-dodecatriene, 2,6- dimethyl-2,4,6-octatriene, 2-phenyl-1 ,3-butadiene, 2-methyl-3-isopropyl-1 ,3-butadiene,
1 .3-cyclohexadiene, myrcene, ocimene, farnasene and combinations thereof.
1 .3-butadiene, isoprene and combinations thereof are the preferred conjugated dienes.
1 .3-butadiene is the most preferred diene.
Typically, the amount of conjugated diene monomer (a) ranges from 15 to 99 wt.-%, preferably from 20 to 95 wt.-%, more preferably from 30 to 75 wt.-%, most preferably from 40 to 70 wt.-%, based on the total weight of the ethylenically unsaturated monomers in the monomer mixture. Thus, the conjugated diene monomer (a) may be present in amounts of at least 15 wt.-%, at least 20 wt.-%, at least 22 wt.-%, at least 24 wt.-%, at least 26 wt.-%, at least 28 wt.-%, at least 30 wt.-%, at least 32 wt.-%, at least 34 wt.-%, at least 36 wt.-%, at least 38 wt.-%, or at least 40 wt.-%, based on the total weight of the ethylenically unsaturated monomers in the monomer mixture. Accordingly, the conjugated diene monomers (a) can be used in amounts of no more than 99 wt.-%, no more than 95 wt.-%, no more than 90 wt.-%, no more than 85 wt.-%, no more than 80 wt.-%, no more than 78 wt.-%, no more than 76 wt.-%, no more than 74 wt.-%, no more than 72 wt.-%, no more than 70 wt.-%, no more than 68 wt.-%, no more than 66 wt.-%, no more than 64 wt.-%, no more than 62 wt.-%, no more than 60 wt.-%, no more than 58 wt.-%, or no more than 56 wt.-%, based on the total weight of the ethylenically unsaturated monomers in the monomer mixture. A person skilled in the art will appreciate that any range between any of the explicitly disclosed lower and upper limit is herein disclosed. According to the present invention it is particularly preferred that the latex particles exhibit a gradient of the concentration of the functional group (a) with a higher concentration of functional groups (a) at the surface of the particles and a lower concentration within the bulk of the particles.
Ethylenically unsaturated nitrile monomers (b) which can be used in the present invention may include polymerizable unsaturated aliphatic nitrile monomers which contain from 2 to 4 carbon atoms in a linear or branched arrangement, which may be substituted either by acetyl or additional nitrile groups. The ethylenically unsaturated nitrile monomers (b) for the preparation of particles of a polymer latex according to the present invention may be selected from acrylonitrile, methacrylonitrile, alpha-cyanoethyl acrylonitrile, fumaronitrile, alpha-chloronitrile and combinations thereof, with acrylonitrile being most preferred.
These nitrile monomers (b) can be included in amounts from 1 to 80 wt.-%, preferably from 10 to 70 wt.-%, or 1 to 60 wt.-%, and more preferred from 15 to 50 wt.-%, even more preferred from 20 to 50 wt.-%, most preferred from 23 to 43 wt.-%, based on the total weight of the ethylenically unsaturated monomers in the monomer mixture. Thus, the unsaturated nitrile (b) may be present in amounts of at least 1 wt.-%, at least 5 wt.-%, at least 10 wt.-%, at least 12 wt.-%, at least 14 wt.-%, at least 15 wt.-%, at least 16 wt.-%, at least 18 wt.-%, at least 20 wt.-%, at least 22 wt.-%, at least 23 wt.-%at least 24 wt.-%, at least 26 wt.-%, at least 28 wt.-%, at least 30 wt.-%, at least 32 wt.-%, at least 34 wt.-%, at least 36 wt.-%, at least 38 wt.-%, or at least 40 wt.-%, based on the total weight of the ethylenically unsaturated monomers in the monomer mixture. Accordingly, the unsaturated nitrile monomers (b) can be used in amounts of no more than 80 wt.-%, no more than 75 wt.-%, no more than 73 wt.-%, no more than 70 wt.-%, no more than 68 wt.-%, no more than 66 wt.-%, no more than 64 wt.-%, no more than 62 wt.-%, no more than 60 wt.-%, no more than 58 wt.-%, no more than 56 wt.-%, no more than 54 wt.-%, no more than 52 wt.-%, no more than 50 wt.-%, no more than 48 wt.-%, no more than 46 wt.-%, or no more than 44 wt.- %, no more than 43 wt.-%, based on the total weight of the ethylenically unsaturated monomers in the monomer mixture. A person skilled in the art will appreciate that any range between any of the explicitly disclosed lower and upper limit is herein disclosed.
Suitable vinyl-aromatic monomers (c) may be selected from styrene, oc-methylstyrene, vinyltoluene, o-methylstyrene, p-methylstyrene, p-tert-butylstyrene, 2,4-dimethylstyrene, 2- methylstyrene, 3-methylstyrene, 4-methylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-ethylstyrene, 2,4-diisopropylstyrene, 2,4-dimethylstyrene, 4-tert-butylstyrene, 5-tert- butyl-2-methylstyrene, 2-chlorostyrene, 3-chlorostyrene, 4-chlorostyrene, 4-bromostyrene, 2-methyl-4,6-dichlorostyrene, 2,4-dibromostyrene, vinylnaphthalene, vinyltoluene, vinylxylene, 2-vinylpyridine, 4-vinylpyridine, 1 ,1 -diphenylethylene and substituted 1 ,1 - diphenylethylene, 1 ,2-diphenylethene and substituted 1 ,2-diphenylethylene, and combinations thereof. Mixtures of one or more of the vinyl-aromatic compounds may also be used. The preferred monomers (c) are styrene and oc-methylstyrene.
The vinyl-aromatic compounds (c) can be used in a range of from 0 to 70 wt.-%, preferably from 1 to 70 wt.-%, more preferred from 10 to 70 wt.-%, even more preferred from 15 to 60 wt.-%, most preferred from 15 to 50 wt.-%, or from 0 to 25 wt.-%, more preferred from 0 to 15 wt.-%, and even more preferred from 0 to 10 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture. Thus, the vinyl-aromatic compound (c) can be present in an amount of no more than 70 wt.-%, no more than 60 wt.-%, no more than 50 wt.-%, no more than 40 wt.-%, no more than 35 wt.-%, no more than 30 wt.-%, no more than 25 wt.-%, no more than 20 wt.-%, no more than 18 wt.-%, no more than 16 wt.-%, no more than 14 wt.-%, no more than 12 wt.-%, no more than 10 wt.-%, no more than 8 wt.-%, no more than 6 wt.-%, no more than 4 wt.-%, no more than 2 wt.-%, or no more than 1 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture. If the vinyl aromatic compound (c) is present, it may be present in amounts of at least 1 wt.-%, at least 2 wt.-%, at least 5 wt.-%, at least 10 wt.-%, at least 15 wt.-%, at least 20 wt.-%, at least 25 wt.-%, at least 30 wt.-%, or at least 35 wt.-% based on the total weight of ethylenically unsaturated monomers in the monomer mixture. A person skilled in the art will appreciate that any range between any of the explicitly disclosed lower and upper limit is herein disclosed.
In the monomer mixture of ethylenically unsaturated monomers for the preparation of the polymer latex of the present invention the sum of ethylenically unsaturated nitrile monomers (b) and vinyl aromatic monomers (c) is 0.95 to 84.95 wt.-% based on the total monomers in the mixture. Thus vinyl-aromatic compounds may also be completely absent. In such a case, ethylenically unsaturated nitrile monomers are mandatorily present and the latex may be considered as a XNBR latex. Alternatively, ethylenically unsaturated nitrile monomers may be completely absent. In such a case, vinyl aromatic monomers are mandatorily present and the latex, particularly if as the preferred conjugated diene butadiene and as preferred vinyl aromatic monomer styrene is selected, may be considered as a XSBR latex. The monomer mixture of ethylenically unsaturated monomers for the preparation of the polymer latex of the present invention comprises 2.5 to 10.0 wt.-% of an ethylenically unsaturated acid (d) comprising an acid functional group; and a spacer group separating the ethylenically unsaturated group and the acid functional group by at least 4 atoms.
According to the present invention, the acid functional group of the ethylenically unsaturated acid (d) may be selected from carboxylic acid groups and phosphorous containing acid groups. Suitable phosphorous containing acid groups may be selected from phosphoric acid groups and phosphonic acid groups. Preferably, the acid functional group of the ethylenically unsaturated acid (d) is selected from carboxylic acid groups.
The ethylenically unsaturated acid (d) may be selected from compounds having the structure:
CHR2=CR1 - A - X, wherein
R1 is selected from H and Ci-C4 alkyl;
R2 is selected from H or - A - X;
A is a divalent spacer group separating the ethylenically unsaturated group and the functional group X by at least 4 atoms independently at each occurrence selected from: - (C(O) - W)n- Y - (O)m- and - (CH2)k - O - (C(O))P- Y - (O)m-; wherein n, m, k and p are integers independently at each occurrence selected from 0 or 1 ; W is - O - or - NR3 -;
R3 is selected from H and Ci-C4 alkyl;
Y is selected from optionally substituted linear, branched, cyclic or aromatic C2 to C3o divalent hydrocarbon or hetero hydrocarbon groups;
X is selected from - C(O)OH and - P(O)(OH)2, preferably - C(O)OH; with the proviso that if X is - C(O)OH m is 0; or
- A - X is selected from - C(O) -O - (Y -C(O) - O)i - H, wherein I is an integer from 2 to 10, preferably from 2 to 7; and mixtures thereof.
Preferably, the ethylenically unsaturated acid (d) is selected from carboxy (C2-C3o)alkyl (meth)acrylates, C7 to C15 fatty acids having a terminal ethylenically unsaturated group mono (meth)acryloyloxy alkyl esters of dicarboxylic esters and more preferred from carboxy (C2-Ci2)alkyl (meth)acrylates and omega-(meth)acryloyoloxy (C2-Ci2)alkyl succinates. Particularly preferred are 2-(meth)acryloyloxyethyl succinate, 2-carboxyethyl acrylate and oligomers thereof having the structure CH2=CH-C(O)-O-(C2H4-C(O)-O)I-H with I being an integer from 2 to 7 and mixtures thereof.
Suitable monomers of ethylenically unsaturated acid (d) are commercially available from Solvay (Belgium) as Sipomer® p-CEA, Sipomer® PAM 100, Sipomer® PAM 200, Sipomer® PAM 300, Sipomer® PAM 4000, and Sipomer® PAM 5000.
Typically, the amount of ethylenically unsaturated acids (d) is from 2.5 to 10.0 wt.-%, particularly from 3.0 to 8.5 wt.-% or 4.5 to 9.0 wt.-%, preferably from 3.4 to 8.0 wt.-%, more preferred from 3.6 to 7.0 wt.-%, even more preferred from 3.6 to 6.5 wt.-%, most preferred 3.6 to 6.0 wt.-%, based on the total weight of the ethylenically unsaturated monomers in the monomer mixture. Thus, the ethylenically unsaturated acid (d) may be present in amounts of at least 2.5 wt.-%, at least 2.7 wt.-%, at least 2.9 wt.-%, at least 3.0 wt.-%, at least 3.2 wt.-%, at least 3.4 wt.-%, at least 3.5 wt.-%, at least 3.6 wt.-%, at least 3.8 wt.-%, at least 3.9 wt.-%, at least 4.0 wt.-%, at least 4.1 wt.-%, at least 4.2 wt.-%, at least 4.3 wt.- %, at least 4.5 wt.-%, or at least 4.6 wt.-%, based on the total weight of the ethylenically unsaturated monomers in the monomer mixture. Likewise, the ethylenically unsaturated acid (d) may be present in amounts of no more than 10 wt.-%, no more than 9.5 wt.-%, no more than 9.0 wt.-%, no more than 8.5 wt.-%, no more than 8.0 wt.-%, no more than 7.5 wt.-%, no more than 7.0 wt.-%, no more than 6.5 wt.-%, no more than 6.0 wt.-%, no more than 5.5 wt.-%, or no more than 5.0 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture. A person skilled in the art will appreciate that any range defined by an explicitly disclosed lower limit and an explicitly disclosed upper limit is disclosed herewith.
According to the present invention, the mixture of ethylenically unsaturated monomers for the preparation of the polymer latex of the present invention may further comprise (f) an ethylenically unsaturated acid being different from the ethylenically unsaturated acid (d). The acid functional group of the ethylenically unsaturated acid (f) may be selected from carboxylic acid groups and phosphorous containing acid groups. Suitable phosphorous containing acid groups may be selected from phosphoric acid groups and phosphonic acid groups. Preferably, the acid functional group of the ethylenically unsaturated acid (f) is selected from carboxylic acid groups.
The ethylenically unsaturated acid (f) can be used in a range of from 0 to 10.0 wt.-%, preferably from 0 to 9.0 wt.-%, more preferred from 0 to 7.0 wt.-%, even more preferred from 0 to 5.0 wt.-%, most preferred from 0 to 3.5 wt.-%, or from 0.5 to 3.5 wt.-%, more preferred from 0.5 to 3.0 wt.-%, and even more preferred from 0.5 to 2.5 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture. Thus, the ethylenically unsaturated acid (f) can be present in an amount of no more than 10.0 wt.-%, no more than 9.5 wt.-%, no more than 8.0 wt.-%, no more than 7.5 wt.-%, 7.0 wt.-%, no more than 6.5 wt.-%, no more than 6.0 wt.-%, no more than 5.5 wt.-%, no more than 5.0 wt.-%, no more than 4.5 wt.-%, no more than 4.2 wt.-%, no more than 4.0 wt.-%, no more than 3.8 wt.-%, no more than 3.6 wt.-%, no more than 3.5 wt.-%, no more than 3.2 wt.-%, no more than 3.0 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture. If the vinyl aromatic compound is present, it may be present in amounts of at least 0.1 wt.-%, at least 0.5 wt.-%, at least 0.7 wt.-%, at least 1 wt.-%, at least 1 .2 wt.-%, at least 1 .3 wt.-%, at least 1 .5 wt.-%, at least 1 .7 wt.-%, or at least 2.0 wt.- %, based on the total weight of ethylenically unsaturated monomers in the monomer mixture. A person skilled in the art will appreciate that any range between any of the explicitly disclosed lower and upper limit is herein disclosed.
According to the present invention, the ethylenically unsaturated acid (d) and the ethylenically unsaturated acid (f) may be present in an amount in the range of up to 10.0 wt.-%, up to 9.5 wt.-%, up to 9.0 wt.-%, up to 8.5 wt.-%, up to 8.0 wt.-%, up to 7.5 wt.- %, up to 7.0 wt.-%, up to 6.5 wt.-%, up to 6.0 wt.-%, up to 5.5 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture. The ethylenically unsaturated acid (d) and the ethylenically unsaturated acid (f) may be present in an amount in the range of at least 3.0 wt.-%, at least 3.2 wt.-%, at least 3.5 wt.-%, at least 3.8 wt.-%, at least 4.0 wt.-%, at least 4.2 wt.-%, at least 4.5 wt.-%, at least 4.8 wt.-%, at least 5.0 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture. A person skilled in the art will appreciate that any range between any of the explicitly disclosed lower and upper limit is herein disclosed. The ethylenically unsaturated acid (d) and the ethylenically unsaturated acid (f) may be present in an amount in the range of from 3.0 to 10.0 wt.-%, preferably from 3.5 to 10.0 wt.-%, more preferably from 4.0 to 9.0 wt.-%, even more preferably from 4.5 to 8.0 wt.-%, most preferably from 5.0 to 7.0 wt.- %, based on the total weight of ethylenically unsaturated monomers in the monomer mixture. The ethylenically unsaturated acid (d) and the ethylenically unsaturated acid (f) may be present in an amount in the range of up to 10.0 wt.-%, preferably up to 9.0 wt.-%, more preferably up to 8.0 wt.-%, even more preferably up to 7.0 wt.-%, most preferably up to 6.0 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture. According to the present invention, the ethylenically unsaturated acid (d) may be the sole ethylenically unsaturated acid. According to the present invention, the ethylenically unsaturated acid (f) or salts may be selected from ethylenically unsaturated carboxylic acids and salts thereof, such as monocarboxylic acid and dicarboxylic acid monomers; ethylenically unsaturated polycarboxylic acid anhydride; and polycarboxylic acid partial ester monomers and salts thereof. It is preferable to use ethylenically unsaturated aliphatic mono- or dicarboxylic acids or anhydrides which contain from 3 to 5 carbon atoms. Ethylenically unsaturated carboxylic acids and salts thereof may be selected from (meth)acrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, cis-cyclohexene-1 ,2-dicarboxylic acid, dimethylmaleic acid, bromomaleic acid, 2,3-dichloromaleic acid and (2-dodecen-1 -yl) succinic acid, vinyl acetic acid, vinyl lactic acid, vinyl sulfonic acid, 2-methyl-2-propene-1 - sulfonic acid, styrene sulfonic acid, acrylamidomethyl propane sulfonic acid and salts thereof; preferably (meth)acrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, and salts thereof. Ethylenically unsaturated polycarboxylic acid anhydride may be selected from maleic anhydride, methacrylic anhydride, cis-cyclohexene-1 ,2-dicarboxylic anhydride, dimethylmaleic anhydride, bromomaleic anhydride, 2,3-dichloromaleic anhydride, citraconic anhydride, crotonic anhydride, itaconic anhydride, and (2-dodecen-1 -yl) succinic anhydride. Polycarboxylic acid partial ester monomers and salts thereof may be selected from monomethyl maleate, monomethyl fumarate, monoethyl maleate, monoethyl fumarate, monopropyl maleate, monopropyl fumarate, monobutyl maleate, monobutyl fumarate, mono(2-ethyl hexyl) maleate, mono(2-ethyl hexyl) fumarate and combinations thereof.
Further, the monomer mixture of ethylenically unsaturated monomers to obtain the polymer latex of the present invention may comprise co-polymerizable ethylenically unsaturated compounds (e).
The co-polymerizable ethylenically unsaturated compounds (e) can be used in a range of from 0 to 65 wt.-%, preferably from 1 to 65 wt.-%, more preferred from 10 to 55 wt.-%, even more preferred from 15 to 50 wt.-%, most preferred from 15 to 40 wt.-%, or from 0 to 25 wt.-%, more preferred from 0 to 15 wt.-%, and even more preferred from 0 to 10 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture. Thus, the co-polymerizable ethylenically unsaturated compounds (e) can be present in an amount of no more than 65 wt.-%, no more than 60 wt.-%, no more than 50 wt.-%, no more than 40 wt.-%, no more than 35 wt.-%, no more than 30 wt.-%, no more than 25 wt.-%, no more than 20 wt.-%, no more than 18 wt.-%, no more than 16 wt.-%, no more than 14 wt.- %, no more than 12 wt.-%, no more than 10 wt.-%, no more than 8 wt.-%, no more than 6 wt.-%, no more than 4 wt.-%, no more than 2 wt.-%, or no more than 1 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture. If the co- polymerizable ethylenically unsaturated compounds (e) is present, it may be present in amounts of at least 1 wt.-%, at least 2 wt.-%, at least 5 wt.-%, at least 10 wt.-%, at least 15 wt.-%, at least 20 wt.-%, at least 25 wt.-%, at least 30 wt.-%, or at least 35 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture. A person skilled in the art will appreciate that any range between any of the explicitly disclosed lower and upper limit is herein disclosed.
According to the invention, the co-polymerizable ethylenically unsaturated compounds (e) may be selected from
(e1 ) alkyl esters of ethylenically unsaturated acids;
(e2) hydroxyalkyl esters of ethylenically unsaturated acids;
(e3) amides of ethylenically unsaturated acids;
(e4) vinyl carboxylates;
(e5) alkoxyalkyl esters of ethylenically unsaturated acids;
(e6) monomers having at least two ethylenically unsaturated groups;
(e7) ethylenically unsaturated silanes; and combinations thereof.
Alkyl esters of ethylenically unsaturated acids (e1 ) that can be used according to the present invention may include n-alkyl esters, iso-alkyl esters or tert-alkyl esters of (meth)acrylic acid in which the alkyl group has from 1 to 20 carbon atoms, the reaction product of methacrylic acid with glycidyl ester of a neoacid such as versatic acid, neodecanoic acid or pivalic acid and hydroxyalkyl (meth)acrylate and alkoxyalkyl (meth)acrylate monomers.
In general, the preferred alkyl esters of ethylenically unsaturated acids (e1 ) may be selected from C1-C10 alkyl (meth)acrylate, preferably Ci-Cs-alkyl (meth)acrylates. Examples of such (meth)acrylate monomers include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, iso-propyl (meth)acrylate, n-butyl (meth)acrylate, secondary butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, hexyl (meth)acrylate, 2-ethyl-hexyl (meth)acrylate, isooctyl (meth)acrylate, 4-methyl-2-pentyl (meth) acrylate, 2-methylbutyl (meth)acrylate, cyclohexyl (meth)acrylate, cetyl (meth)acrylate and combinations thereof. Methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, iso-propyl (meth) acyl ate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate and combinations thereof are preferred. Typically, the alkyl esters of ethylenically unsaturated acids (e1 ) can be present in an amount of no more than 18 wt.-%, no more than 16 wt.-%, no more than 14 wt.-%, no more than 12 wt.-%, no more than 10 wt.-%, no more than 8 wt.-%, no more than 6 wt.-%, no more than 4 wt.-%, no more than 2 wt.-%, or no more than 1 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture.
The hydroxyalkyl esters of ethylenically unsaturated acids (e2), which can be used to prepare the polymer latex according to the present invention, may include hydroxyalkyl acrylate and methacrylate monomers which are based on ethylene oxide, propylene oxide and higher alkylene oxides or mixtures thereof. Suitable examples of hydroxyalkyl esters of ethylenically unsaturated acids (e2) may be selected from hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, and combinations thereof. Preferably, the hydroxyalkyl esters of ethylenically unsaturated acids (e2) is 2-hydroxy ethyl(meth)acrylate. Typically, hydroxyalkyl esters of ethylenically unsaturated acids (e2) can be present in an amount of no more than 18 wt.-%, no more than 16 wt.-%, no more than 14 wt.-%, no more than 12 wt.-%, no more than 10 wt.-%, no more than 8 wt.-%, no more than 6 wt.-%, no more than 4 wt.-%, no more than 2 wt.-%, or no more than 1 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture. Amides of ethylenically unsaturated acids (e3) that can be used for the preparation of the polymer latex according to the present invention may be selected from (meth)acryl amide, diacetone acrylamide, and combinations thereof. The preferred amide monomer is (meth)acrylamide. In order to introduce functional groups that are capable of selfcrosslinking upon heat treatment into the polymer particles of the present invention monomers comprising N-methylol amide groups may be employed. Suitable monomers are N-methylol (meth)acrylamide, N-methoxymethyl (meth)acrylamide, N-n-butoxy-methyl (meth)acrylamide, N-iso-butoxy-methyl (meth)acrylamide, N-acetoxymethyl (meth)acrylamide, N-(2,2-dimethoxy-1 -hydroxyethyl) acrylamide. Typically, amides of ethylenically unsaturated acids (e3) can be present in an amount of no more than 18 wt.-%, no more than 16 wt.-%, no more than 14 wt.-%, no more than 12 wt.-%, no more than 10 wt.-%, no more than 8 wt.-%, no more than 6 wt.-%, no more than 4 wt.-%, no more than 2 wt.-%, or no more than 1 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture.
Vinyl carboxylates (e4), which can be used according to the present invention, may be selected from vinyl acetate, vinyl propionate, vinyl butyrate, vinyl benzoate, vinyl-2- ethylhexanoate, vinyl stearate, vinyl esters of versatic acid, and combinations thereof. The most preferred vinyl carboxylate monomer (e4) for use in the present invention is vinyl acetate. Typically, the vinyl carboxylates (e4) can be present in an amount of no more than 18 wt.-%, no more than 16 wt.-%, no more than 14 wt.-%, no more than 12 wt.-%, no more than 10 wt.-%, no more than 8 wt.-%, no more than 6 wt.-%, no more than 4 wt.-%, no more than 2 wt.-%, or no more than 1 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture.
Alkoxyalkyl esters of ethylenically unsaturated acids (e5) which can be used in the present invention may be selected from methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, methoxybutyl (meth)acrylate, methoxyethoxyethyl (meth)acrylate and combinations thereof. Preferred alkoxyalkyl esters of ethylenically unsaturated acids (e5) are ethoxyethyl acrylate and methoxyethyl acrylate. Typically, the alkoxyalkyl esters of ethylenically unsaturated acids (e5) can be present in an amount of no more than 18 wt.-%, no more than 16 wt.-%, no more than 14 wt.-%, no more than 12 wt.-%, no more than 10 wt.-%, no more than 8 wt.-%, no more than 6 wt.-%, no more than 4 wt.-%, no more than 2 wt.-%, or no more than 1 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture.
Suitable monomers having at least two ethylenically unsaturated groups (e6) may be selected from divinyl benzene and di(meth)acrylates, such as ethylene glycol di(meth)acrylate, hexanediol di(meth)acrylate, tripropylene glycol di(meth)acrylate, butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, and dipropylene glycol di(meth)acrylate. The monomers having at least two ethylenically unsaturated groups (e6) are preferably selected from divinyl benzene, 1 ,2-ethyleneglycol di(meth)acrylate, 1 ,4-butanediol di(meth)acrylate and 1 ,6-hexanediol di(meth)acrylate. More preferred monomers having at least two ethylenically unsaturated groups (e6) may be selected from divinyl benzene, ethylene glycol dimethacrylate and 1 ,4 butanediol di(meth)acrylate. The monomers having at least two ethylenically unsaturated groups (6) may be present in an amount of less than 5 wt.-%, preferably less than 4 wt.-%, particularly preferred less than 3 wt.-%, more preferred less than 2.5 wt.-%, even more preferred less than 2 wt.-%, most preferred less than 1.5 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture. The monomer mixture may be free of monomers having at least two ethylenically unsaturated groups (e6).
Suitable ethylenically unsaturated silanes (e7) may be selected from vinyl trialkoxysilanes, allyl trialkoxysilanes, 3-(meth)acryloxy propyl trialkoxysilanes and combinations thereof. The ethylenically unsaturated silanes (e7) may be present in an amount of less than 5 wt.- %, preferably less than 4 wt.-%, more preferred less than 3 wt.-%, even more preferred less than 2.5 wt.-%, even more preferred less than 2 wt.-%, even more preferred less than 1 .5 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture. The monomer mixture may be free of ethylenically unsaturated silanes (e7).
According to the present invention, the amounts of the above-defined monomers for the preparation of the latex polymer may add up to 100 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture.
The mixture of ethylenically unsaturated monomers to obtain the latex polymer of the present invention may comprise:
(a) 20 to 98 wt.-% of conjugated dienes, preferably selected from butadiene, isoprene and combinations, thereof, more preferred butadiene;
(b) 1 to 60 wt.-% of ethylenically unsaturated nitrile monomers, preferably acrylonitrile;
(c) 0 to 40 wt.-% of vinyl aromatic monomers, preferably styrene;
(d) 3.0 to 10.0 wt.-% of ethylenically unsaturated acids comprising an acid functional group, and a spacer group separating the ethylenically unsaturated group and the acid functional group by at least 4 atoms, preferably selected from 2-(meth)acryloyloxyethyl succinate, 2-carboxyethyl acrylate and oligomers thereof having the structure CH2=CH- C(O)-O-(C2H4-C(O) — O)I— H with I being an integer from 2 to 7;
(e1 ) 0 to 25 wt.-% of Ci to Cs alkyl (meth)acrylates;
(e3) 0 to 10 wt.-% of amides of ethylenically unsaturated acids;
(e4) 0 to 10 wt.-% of vinyl esters;
(e7) 0 to 10 wt.-% of ethylenically unsaturated silanes;
(f) 0 to 10.0 wt.-% of ethylenically unsaturated acids different from (d), the weight percentages being based on the total weight of the ethylenically unsaturated monomers in the monomer mixture. The amounts of the above-defined monomers for the preparation of polymer latex may add up to 100 wt.-%.
According to the present invention, the latex polymer may be free of any ethylenically unsaturated acids different from (d).
The polymer latex composition of the present invention may be substantially free of a biocide. As used herein, the term “substantially free” means that the biocide is present, if at all, as an incidental impurity, such as in an amount of less than 0.04 wt.-%, based on the total weight of the polymer latex composition. According to the present invention, the polymer latex composition may be completely free of a biocide. As used herein, the term “completely free” means that a biocide is not present in the polymer latex composition at all. As used herein, the term “biocide” refers to compounds used to prevent the growth and/or to inhibit unwanted microorganisms selected from the group comprising at least one strain of bacteria, at least one strain of fungi, mould, yeast, algae and mixtures thereof.
Examples of biocides may be selected from the group comprising phenols, such as 2-phenylphenol or 2-phenylphenol in the form of an alkali metal salt such as sodium salt or potassium salt; halogenated phenols, such as 4-chloro-3-methylphenol or 4-chloro-2- methylphenol; halogen-containing compounds or halogen-releasing compounds, such as bronopol, bronidox, 2,2-dibrom-3-nitrilpropionamid, 1 ,2- dibromo-2,4-dicyanobutane, monochloroamine, ammonium bromide, calcium hypochlorite, iodine, tri-iodide or potassium iodate; isothiazolinones, such as isothiazolinone, benzisothiazolinone, 5-chloro- 2-methyl-2H-isothiazolin-3-one, 2-methyl-2H-isothiazolin-3-one, octylisothiazolinone or dichlorooctylisothiazolinone; aldehyde-containing compounds, such as formaldehyde, acetaldehyde, glyoxal, glutaraldehyde, 2-propenal or phthalic dialdehyde; aldehyde- releasing compounds, such as benzyl alcohol mono(poly)-hemiformal, tetramethylolacetylenediurea, thiadiazinethione-tetrahydrodimethyl,
(ethylenedioxy)dimethanol, 2-chloro-N-(hydroxymethyl)acetamide, dimethyloxazolidine, hexamethylenetetramine, bis[tetrakis(hydroxymethyl)phosphonium] sulphate, 1 -(cis-3- chloroallyl)-3,5,7-triaza-1 -azoniaadamantane chloride or hexahydro-1 ,3,5- tris(hydroxyethyl)-s-triazine; guanidines, such as guanidinedodecyl monochloride or polyethoxyethoxyethylguanidinium hexachloride; sulfones, such as hexachlorodimethyl sulfone or 4,4’-diaminodiphenylsulfone; thiocyanates, such as methylene bis(thiocyanate) or (benzothiazol-2-ylthio)methyl thiocyanate; pyrithiones, such as sodium pyrithione or zinc pyrithione; antibiotics such as p-lactam antibiotics, such as such as penicillin G, ampicillin, biapenem or cefixime; quaternary ammonium salts; peroxides; perchlorates; amides, such as 2,2-dibromo-3-nitrilopropionamide; amines; biocidal enzymes; biocidal polypeptides; azoles, such as climbazole, miconazole, clotrimazole; carbamates, such as iodopropynyl butylcarbamate, aldicarb or carbofuran; glyphosates, such as N-(phosphonomethyl)glycine or N-(phosphonomethyl)glycine in the form of a salt such as ammonium salt or isopropylammonium salt; sulphonamides and mixtures thereof.
The pH of the polymer latex composition of the present invention is lower than 7.5, preferably lower than or equal to 7.4, more preferably lower than or equal to 7.2, even more preferably lower than or equal to 7.1 , most preferably lower than or equal to 7.0. The pH of the polymer latex composition of the present invention may be at least 2.0, at least 2.5, at least 3.0, at least 3.5, at least 4.0, at least 4.5, at least 5.0, at least 5.5, at least 5.8, at least 6.0, at least 6.2, at least 6.4, at least 6.5. The pH of the polymer latex composition of the present invention may be up to 7.4, up to 7.3, up to 7.2, up to 7.1 , up to 7.0, up to 6.9. A person skilled in the art will appreciate that any range between any of the explicitly disclosed lower and upper limit is herein disclosed. The pH of the polymer latex composition of the present invention may be in the range of 6.0 to less than 7.5, preferably 6.0 to 7.4, more preferably 6.0 to 7.2, even more preferably 6.5 to 7.2, most preferably 6.7 to 7.2. The pH may be determined according to DIN ISO 976. According to the present invention, the pH may be adjusted using a pH modifier selected from sodium hydroxide, potassium hydroxide, ammonia solution, preferably ammonia solution.
The polymer latex composition of the present invention can be prepared by first making the polymer latex as described above and then combining the obtained polymer latex with an oxirane functional compound. In the polymer latex composition of the present invention the carboxylic acid functional latex polymer of the present invention and the oxirane functional compound may be present in relative amounts to provide a molar ratio of oxirane groups to carboxylic acid groups from 0.1 to 2.0, preferably from 0.1 to 1.5, more preferred from 0.2 to 0.9, most preferred from 0.3 to 0.6.
The oxirane functional compound may be selected from i) a latex polymer, preferably a butadiene acrylonitrile latex polymer bearing a plurality of oxirane functional groups; ii) monomeric or oligomeric compounds comprising at least two oxirane functional groups; and iii) monomeric compounds, oligomeric or polymeric compounds that are not prepared be free-radical addition polymerization bearing at least one oxirane group and a functional group different from an oxirane group, said functional groups different from an oxirane group on different molecules of compound iii) are capable of reacting with each other.
The latex polymer i) may be selected from oxirane functional latex polymers as disclosed in WO 2017/209596.
Suitable monomeric or oligomeric compounds comprising at least two oxirane functional groups ii) may be selected from ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, poly (ethylene glycol) diglycidyl ether, polypropylene glycol) diglycidyl ether, bisphenol-A diglycidyl ether, and combinations thereof. Preferably, compound ill) is selected from oxirane functional di- or tri alkoxysilanes, more preferred from (3-glycidoxypropyl) trialkoxysilanes.
Without wanting to be bound by theory, it is believed that when forming an elastomeric film from a latex composition comprising the carboxylated polymer latex of the present invention and an oxirane functional compound thermally labile beta-hydroxy ester linkages such as cross-links are formed. Upon application of thermal energy these labile beta-hydroxy ester linkages or cross-links my break up and subsequently reform again, with the result that such elastomeric films show self-healing properties and can be repaired and recycled providing an additional advantage to the present invention.
Method for the preparation of the polymer latex composition of the present invention
The method for preparing a polymer latex composition comprises preparing a polymer latex by free-radical emulsion polymerization of a mixture of ethylen ically unsaturated monomers comprising:
(a) 15 to 99 wt.-% of conjugated dienes;
(b) 0 to 80 wt.-% of ethylenically unsaturated nitrile monomers;
(c) 0 to 70 wt.-% of vinyl aromatic monomers; the sum of ethylenically unsaturated nitrile monomers (b) and vinyl aromatic monomers (c) being 0.95 to 84.95 wt.-%;
(d) 2.5 to 10.0 wt.-% of an ethylenically unsaturated acid comprising an acid functional group; and a spacer group separating the ethylenically unsaturated group and the acid functional group by at least 4 atoms;
(e) 0 to 65 wt.-% of co-polymerizable ethylenically unsaturated compounds, and
(f) 0 to 10.0 wt.-%, of an ethylenically unsaturated acid being different from (d); wherein monomers (a) to (f) are different from each other and the weight percentages being based on the total weight of the ethylenically unsaturated monomers in the monomer mixture; and adjusting the pH of the polymer latex composition to be lower than 7.5.
All variations with respect to the monomers used for the preparation of the polymer latex of the present invention and their relative amounts can be as described above.
The polymer latex according to the present invention can be made by any emulsion polymerization process known to a person skilled in the art, provided that the monomer mixture as herein defined is employed. Particularly suitable is the process as described in EP-A 792 891.
In the emulsion polymerization for preparing the polymer latex of the present invention, a seed latex may be employed. Any seed particles as known to the person skilled in the art can be used.
The seed latex particles are preferably present in an amount of 0.01 to 10 parts by weight, preferably 1 to 5 parts by weight, based on 100 parts by weight of total ethylenically unsaturated monomers employed in the polymer. The lower limit of the amount of seed latex particles therefore can be 0.01 , 0.05, 0.1 , 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1 .0, 1.1 , 1 .2, 1 .3, 1 .4, 1 .5, 1 .6, 1 .7, 1 .8, 1 .9, 2.0, 2.1 , 2.2, 2.3, 2.4, or 2.5 parts by weight. The upper limit of the amount can be 10, 9, 8, 7, 6, 5.5, 5, 4.5, 4, 3.8, 3.6, 3.4, 3.3, 3.2, 3.1 or 3 parts by weight. A person skilled in the art will understand that any range formed by any of the explicitly disclosed lower limits and upper limits is explicitly encompassed in the present specification.
The process for the preparation of the above-described polymer latex can be performed at temperatures of from 0 to 130 °C, preferably of from 0 to 100 °C, particularly preferably of from 5 to 70 °C, very particularly preferably of from 5 to 60 °C, in the presence of no or one or more emulsifiers, no or one or more colloids and one or more initiators. The temperature includes all values and sub-values therebetween, especially including 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120 and 125 °C.
Initiators which can be used when carrying out the present invention may include water- soluble and/or oil-soluble initiators which are effective for the purposes of the polymerization. Representative initiators are well known in the technical area and include, for example: azo compounds (such as, for example, AIBN, AMBN and cyanovaleric acid) and inorganic peroxy compounds, such as hydrogen peroxide, sodium, potassium and ammonium peroxydisulfate, peroxycarbonates and peroxyborates, as well as organic peroxy compounds, such as alkyl hydroperoxides, dialkyl peroxides, acyl hydroperoxides, and diacyl peroxides, as well as esters, such as tert-butyl perbenzoate and combinations of inorganic and organic initiators. Suitable initiators may be selected from 2,3-dimethyl- 2,3-diphenylbutane, tert-butyl hydroperoxide, tert-amyl hydroperoxide, cumyl hydroperoxide, 1 ,1 ,3,3-tetramethylbutyl hydroperoxide, isopropylcumyl hydroperoxide, 2,5- di(tert-butylperoxy)-2,5-dimethyl-3-hexyne, 3,6,9-triethyl-3,6,9-trimethyl-1 ,4,7- triperoxonane, di(tert-butyl)peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, di(tert- butylperoxy-isopropyl)benzene, tert-butyl cumyl peroxide, di-(tert-amyl)-peroxide, dicumyl peroxide, butyl 4,4-di(tert-butylperoxy)valerate, tert-butylperoxybenzoate, 2,2-di(tert- butylperoxy)butane, tert-amyl peroxy-benzoate, tert-butylperoxy-acetate, tert-butylperoxy- (2-ethylhexyl)carbonate, tert-butylperoxy isopropyl carbonate, tert-butyl peroxy-3,5,5- trimethyl-hexanoate, 1 ,1 -di(tert-butylperoxy)cyclohexane, tert-amyl peroxyacetate, tert- amylperoxy-(2-ethylhexyl)carbonate, 1 ,1 -di(tert-butylperoxy)-3,5,5-trimethylcyclohexane, 1 ,1 -di(tert-amylperoxy)cyclohexane, tert-butyl-monoperoxy-maleate,
1 ,1 ’-azodi(hexahydrobenzonitrile), tert-butyl peroxy-isobutyrate, tert-butyl peroxydiethylacetate, tert-butyl peroxy-2-ethylhexanoate, dibenzoyl peroxide, tert-amyl peroxy-2-ethylhexanoate, di(4-methylbenzoyl)peroxide, 1 ,1 ,3,3-tetramethylbutyl peroxy-2- ethylhexanoate, ammoniumperoxodisulfate, 2,5-dimethyl-2,5-di(2- ethylhexanoylperoxy)hexane, 2,2’-azodi(2-methylbutyronitrile), 2,2’-azodi(isobutyronitrile), didecanoyl peroxide, potassium persulfate, dilauroyl peroxide, di(3,5,5-trimethylhexanoyl) peroxide, tert-amyl peroxypivalate, tert-butyl peroxyneoheptanoate, 1 ,1 ,3,3-tetramethylbutyl peroxypivalate, tert-butyl peroxypivalate, dicetyl peroxydicarbonate, dimyristyl peroxydicarbonate, di(2-ethylhexyl) peroxydicarbonate, di(4- tert-butylcyclohexyl) peroxydicarbonate, diisopropyl peroxydicarbonate, tert-butyl peroxyneodecanoate, di-sec-butyl peroxydicarbonate, tert-amyl peroxyneodecanoate, cumyl peroxyneoheptanoate, di(3-methoxybutyl) peroxydicarbonate, 1 ,1 ,3,3-tetramethylbutyl peroxyneodecanoate, cumyl peroxyneodecanoate, diisobutyryl peroxide, hydrogen peroxide, and mixture thereof.
The initiator may be used in a sufficient amount to initiate the polymerization reaction at a desired rate. In general, an amount of initiator of from 0.01 to 5 wt.-%, preferably of from 0.1 to 4 wt.-%, based on the total weight of monomers in the monomer mixture, is sufficient. The amount of initiator is most preferably of from 0.01 to 2 wt.-%, based on the total weight of monomers in the monomer mixture. The amount of initiator includes all values and subvalues therebetween, especially including 0.01 , 0.1 , 0.5, 1 , 1.5, 2, 2.5, 3, 4 and 4.5 wt.-%, based on the total weight of monomers in the monomer mixture.
The above-mentioned inorganic and organic peroxy compounds may also be used alone or in combination with one or more suitable reducing agents, as is well known in the art. Examples of such reducing agents may include sulfur dioxide, alkali metal disulfites, alkali metal and ammonium hydrogen sulfites, thiosulfates, dithionites and formaldehyde sulfoxylates, as well as hydroxylamine hydrochloride, hydrazine sulfate, iron (II) sulfate, cuprous naphthanate, glucose, sulfonic acid compounds such as sodium methane sulfonate, amine compounds such as dimethylaniline and ascorbic acid. The quantity of the reducing agent is preferably 0.03 to 10 parts by weight per part by weight of the polymerization initiator.
Surfactants or emulsifiers which are suitable for stabilizing the latex particles may include those conventional surface-active agents for polymerization processes. The surfactant or surfactants can be added to the aqueous phase and/or the monomer phase. An effective amount of surfactant in a seed process is the amount which was chosen for supporting the stabilization of the particle as a colloid, the minimization of contact between the particles and the prevention of coagulation. In a non-seeded process, an effective amount of surfactant is the amount which was chosen for influencing the particle size.
Representative surfactants include saturated and ethylenically unsaturated sulfonic acids or salts thereof, including, for example, unsaturated hydrocarbonsulfonic acid, such as vinylsulfonic acid, allylsulfonic acid and methallylsulfonic acid, and salts thereof; aromatic hydrocarbon acids, such as, for example, p-styrenesulfonic acid, isopropenylbenzenesulfonic acid and vinyloxybenzenesulfonic acid and salts thereof; sulfoalkyl esters of acrylic acid and methacrylic acid, such as, for example, sulfoethyl methacrylate and sulfopropyl methacrylate and salts thereof, and 2-acrylamido-2- methylpropanesulfonic acid and salts thereof; alkylated diphenyl oxide disulfonates, sodium dodecylbenzenesulfonates and dihexyl esters of sodium sulfosuccinate, sodium alkyl esters of sulfonic acid, ethoxylated alkylphenols and ethoxylated alcohols; and fatty alcohol (poly)ethersulfates.
The type and the amount of the surfactant is governed typically by the number of particles, their size and their composition. Typically, the surfactant is used in amounts of from 0 to 20 wt.-%, preferably from 0 to 10 wt.-%, more preferably from 0 to 5 wt.-%, based on the total weight of the monomers in the monomer mixture. The amount of surfactant includes all values and sub-values therebetween, especially including 0, 0.1 , 0.5, 1 , 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 , 12, 13, 14, 15, 16, 17, 18 and 19 wt.-%, based on the total weight of the monomer in the monomer composition. The polymerization may be conducted without using surfactants.
Various protective colloids can also be used instead of or in addition to the surfactants described above. Suitable colloids include polyhydroxy compounds, such as partially acetylated polyvinyl alcohol, casein, hydroxyethyl starch, carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, polysaccharides, and degraded polysaccharides, polyethylene glycol and gum arable. The preferred protective colloids are carboxymethylcellulose, hydroxyethylcellulose and hydroxypropylcellulose. In general, these protective colloids are used in contents of from 0 to 10 parts by weight, preferably from 0 to 5 parts by weight, more preferably from 0 to 2 parts by weight, based on the total weight of the monomers. The amount of protective colloids includes all values and subvalues therebetween, especially including 1 , 2, 3, 4, 5, 6, 7, 8 and 9 wt.-%, based on the total weight of the monomers.
The person skilled in the art will appreciate the type and amounts of monomers bearing polar functional groups, surfactants and protective colloids that are to be selected to make the polymer latex according to the present invention suitable for dip-molding applications. Thus, it is preferred that the polymer latex composition of the present invention has a certain maximum electrolyte stability determined as critical coagulation concentration of less than 30 mmol/l CaCI2, preferably less than 25 mmol/l CaCI2, more preferred less than 20 mmol/l CaCI2, most preferred less than 10 mmol/l CaCI2 (determined for a total solids content of the composition of 0.1% at pH 10 and 23°C).
If the electrolyte stability is too high, then it will be difficult to coagulate the polymer latex in a dip-molding process, with the result that either no continuous film of the polymer latex on the immersed mold is formed or the thickness of the resulting product is non-uniform.
It is within the routine of the person skilled in the art to appropriately adjust the electrolyte stability of a polymer latex. The electrolyte stability will depend on certain different factors, for example, amount and selection of monomers to be used for making the polymer latex, especially monomers containing polar-functional groups, as well as the selection and amount of the stabilizing system, for example, the emulsion polymerization process for making the polymer latex. The stabilizing system may contain surface-active agents and/or protective colloids.
A person skilled in the art is able, depending on the selected monomers and their relative amounts for making the polymer latex of the present invention, to adjust the stabilizing system in order to achieve an electrolyte stability according to the present invention.
It is frequently advisable to perform the emulsion polymerization additionally in the presence of buffer substances and chelating agents. Suitable substances are, for example, alkali metal phosphates and pyrophosphates (buffer substances) and the alkali metal salts of ethylenediaminetetraacetic acid (EDTA) or hydroxyl-2-ethylenediaminetriacetic acid (HEEDTA) as chelating agents. The quantity of buffer substances and chelating agents is usually 0.001 -1.0 wt.-%, based on the total quantity of monomers.
Furthermore, it may be advantageous to use chain transfer agents (regulators) in emulsion polymerization. Typical agents are, for example, organic sulfur compounds, such as thioesters, 2-mercaptoethanol, 3-mercaptopropionic acid and C1-C12 alkyl mercaptans, n-dodecylmercaptan and t-dodecylmercaptan being preferred. The quantity of chain transfer agents, if present, is usually 0.05-3.0 wt.-%, preferably 0.2-2.0 wt.-%, based on the total weight of the used monomers.
Furthermore, it can be beneficial to introduce partial neutralization to the polymerization process. A person skilled in the art will appreciate that by appropriate selection of this parameter the necessary control can be achieved.
Various other additives and ingredients can be added in order to prepare the latex composition of the present invention. Such additives include, for example: antifoams, wetting agents, thickeners, plasticizers, fillers, pigments, dispersants, optical brighteners, crosslinking agents, accelerators, antioxidants, biocides and metal chelating agents. Known antifoams include silicone oils and acetylene glycols. Customary known wetting agents include alkylphenol ethoxylates, alkali metal dialkylsulfosuccinates, acetylene glycols and alkali metal alkylsulfate. Typical thickeners include polyacrylates, polyacrylamides, xanthan gums, modified celluloses or particulate thickeners, such as silicas and clays. Typical plasticizers include mineral oil, liquid polybutenes, liquid polyacrylates and lanolin. Zinc oxide is a suitable crosslinking agent. Titanium dioxide (TiOz), calcium carbonate and clay are the fillers typically used. Known accelerators and secondary accelerators include dithiocarbamates like zinc diethyl dithiocarbamate, zinc dibutyl dithiocarbamate, zinc dibenyl dithiocarbamate, zinc pentamethylene dithiocarbamate (ZPD), xanthates, thiurams like tetramethylthiuram monosulfide (TMTM), tetramethylthiuram disulfide (TMTD), tetraethylthiuram disulfide (TETD), dipentamethylenethiuram hexasulfide (DPTT), and amines, such as diphenylguanidine (DPG), di-o-tolylguanidine (DOTG), and o-tolylbiguanidine (OTBG). Preferably, the polymer latex composition is free of any biocides.
Compounded latex composition for the production of dip-molded articles
The polymer latex of the present invention is particularly suitable for dip-molding processes. Therefore, the polymer latex or the polymer latex composition of the present invention is compounded to produce a curable polymer latex compound composition that can be directly used in dip-molding processes.
The compounded latex composition suitable for the production of dip-molded articles comprises the polymer latex composition of the present invention or obtained by the method for preparing a polymer latex composition of the present invention.
All variations with respect to the monomers used for the preparation of the polymer latex of the present invention and their relative amounts can be as described above.
Preferably, the monomer mixture may further comprise an ethylenically unsaturated acid (f).The ethylenically unsaturated acid (f) can be present in an amount of no more than 10.0 wt.-%, no more than 9.5 wt.-%, no more than 8.0 wt.-%, no more than 7.5 wt.-%, 7.0 wt.-%, no more than 6.5 wt.-%, no more than 6.0 wt.-%, no more than 5.5 wt.-%, no more than 5.0 wt.-%, no more than 4.5 wt.-%, no more than 4.2 wt.-%, no more than 4.0 wt.- %, no more than 3.8 wt.-%, no more than 3.6 wt.-%, no more than 3.5 wt.-%, no more than 3.2 wt.-%, no more than 3.0 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture. If the ethylenically unsaturated acid (f) is present it may be present in amounts of at least 0.1 wt.-%, at least 0.5 wt.-%, at least 0.7 wt.-%, at least 1 wt.-%, at least 1 .2 wt.-%, at least 1 .3 wt.-%, at least 1 .5 wt.-%, at least 1 .7 wt.-%, or at least 2.0 wt.-% based on the total weight of ethylenically unsaturated monomers in the monomer mixture. A person skilled in the art will appreciate that any range between any of the explicitly disclosed lower and upper limit is herein disclosed. Thus, the ethylenically unsaturated acid (f) can be present in a range of from 0.1 to 10.0 wt.-%, preferably from 0.1 to 9.0 wt.-%, more preferred from 0.1 to 7.0 wt.-%, even more preferred from 0.5 to 5.0 wt.-%, most preferred from 0.5 to 3.5 wt.-%, or from 0.5 to 3.5 wt.-%, more preferred from 0.5 to 3.0 wt.-%, and even more preferred from 0.5 to 2.5 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture.
According to the present invention, the ethylenically unsaturated acid (d) and the ethylenically unsaturated acid (f) may be present in an amount in the range of up to 10.0 wt.-%, up to 9.5 wt.-%, up to 9.0 wt.-%, up to 8.5 wt.-%, up to 8.0 wt.-%, up to 7.5 wt.- %, up to 7.0 wt.-%, up to 6.5 wt.-%, up to 6.0 wt.-%, up to 5.5 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture. The ethylenically unsaturated acid (d) and the ethylenically unsaturated acid (f) may be present in an amount in the range of at least 3.0 wt.-%, at least 3.2 wt.-%, at least 3.5 wt.-%, at least 3.8 wt.-%, at least 4.0 wt.-%, at least 4.2 wt.-%, at least 4.5 wt.-%, at least 4.8 wt.-%, at least 5.0 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture. A person skilled in the art will appreciate that any range between any of the explicitly disclosed lower and upper limit is herein disclosed. The ethylenically unsaturated acid (d) and the ethylenically unsaturated acid (f) may be present in an amount in the range of from 3.0 to 10.0 wt.-%, preferably from 3.5 to 10.0 wt.-%, more preferably from 4.0 to 9.0 wt.-%, even more preferably from 4.5 to 8.0 wt.-%, most preferably from 5.0 to 7.0 wt.- %, based on the total weight of ethylenically unsaturated monomers in the monomer mixture. The ethylenically unsaturated acid (d) and the ethylenically unsaturated acid (f) may be present in an amount in the range of up to 10.0 wt.-%, preferably up to 9.0 wt.-%, more preferably up to 8.0 wt.-%, even more preferably up to 7.0 wt.-%, most preferably up to 6.0 wt.-%, based on the total weight of ethylenically unsaturated monomers in the monomer mixture. According to the present invention, the ethylenically unsaturated acid (d) may be the sole ethylenically unsaturated acid.
According to the present invention, the compounded latex composition may further comprise adjuvants selected from sulfur vulcanization agents, accelerators for sulfur vulcanization, crosslinkers, polyvalent cations and combinations thereof. The presence of multivalent cations, preferably ZnO, preferably in amounts of 0.5 wt.-% to 2.5 wt.-% of ZnO based on solid latex polymer of ZnO is preferred.
In particular the compounded latex composition of the present invention may comprise 0 to 2.8 wt.-%, preferably 0.5 to 2.8 wt.-%, more preferred 1 .0 to 2.0 wt.-%, most preferred 1 .5 to 2.0 wt.-% sulfur and 0.0 to 2.8 wt.-%, preferably 1 .0 to 2.0 wt.-%, more preferred 1 .2 to 1.8 wt.-% of sulfur vulcanization agents and 0.5 wt.-% to 2.5 wt.-% of ZnO the weight percentages being based on solid latex polymer. If crosslinkers such as the oxirane functional compounds as discussed above are present sulfur vulcanization agents may be omitted.
To get reproducible good physical film properties, it is advisable to adjust the pH of the compounded polymer latex composition by pH modifiers to be in the range of pH 7 to 13, preferably 10.5 to 13, more preferred 1 1 to 12, for dipping to produce thin disposable gloves. For producing unsupported and/or supported reusable gloves, it is advisable to adjust the pH of the compounded polymer latex composition by pH modifiers to be in the range of pH 8 to 10, preferably 8.5 to 9.5. The compounded polymer latex composition contains the polymer latex of the present invention, optionally the pH modifiers, preferably ammonia or alkali hydroxides and optionally usual additives to be used in these compositions selected from antioxidants, pigments, TiO2, fillers and dispersing agents. Various other additives and ingredients can be added in order to prepare the latex composition of the present invention. Such additives include, for example: antifoams, wetting agents, thickeners, plasticizers, fillers, pigments, dispersants, optical brighteners, antioxidants, biocides and metal chelating agents. Preferably, the compounded polymer latex is substantially free of biocides and even more preferably the compounded polymer latex is completely free of biocides. Known antifoams include silicone oils and acetylene glycols. Customary known wetting agents include alkylphenol ethoxylates, alkali metal dialkylsulfosuccinates, acetylene glycols and alkali metal alkylsulfate. Typical thickeners include polyacrylates, polyacrylamides, xanthan gums, modified celluloses or particulate thickeners, such as silicas and clays. Typical plasticizers include mineral oil, liquid polybutenes, liquid polyacrylates and lanolin. Titanium dioxide (TiO2), calcium carbonate and clay are the fillers typically used.
The method for making dip-molded articles
The present invention relates to a method for making dip-molded articles. In a suitable method for making dip-molded latex articles according to the present invention, first, a clean mold having the desired shape of the final article is immersed in a coagulant bath comprising a solution of a metal salt. The coagulant is usually used as a solution in water, an alcohol or a mixture thereof. As specific examples of the coagulant the metal salts can be metal halides like calcium chloride, magnesium chloride, barium chloride, zinc chloride and aluminum chloride; metal nitrates such as calcium nitrate, barium nitrate and zinc nitrate; metal sulfates like calcium sulfate, magnesium sulfate, and aluminum sulfate; and acetic acid salts such as calcium acetate, barium acetate and zinc acetate. Most preferred are calcium chloride and calcium nitrate. The coagulant solution might contain additives to improve the wetting behavior of the former.
Thereafter, the mold is removed from the bath and optionally dried. The such treated mold is then immersed in the compounded latex composition according to the present invention. Thereby, a thin film of latex is coagulated on the surface of the mold. It is known in the art that the thickness of the thus dipped film may be influenced by the concentration of the compounded latex and/or the length of time that the salt-coated mold is in contact with the compounded latex. Alternatively, it is also possible to obtain the latex film by a plurality of dipping steps, particularly two dipping steps in sequence.
Thereafter, the mold is removed from the latex composition and optionally immersed in a water bath in order to extract, for example, polar components from the composition and to wash the coagulated latex film. Thereafter, the latex coated mold is optionally dried at temperature below 80°C.
Finally, the latex coated mold is heat-treated at a temperature of 40 to 180°C, preferably at a temperature of 70 to 120°C in order to obtain the desired mechanical properties for the final film product. Then, the final latex film is removed from the mold. The duration of the heat treatment will depend on the temperature and is typically between 1 and 60 min. The higher the temperature, the shorter is the required treatment time.
According to the present invention, the compounded latex composition can be matured for at least 3 h, preferably from 24 to 48 h, after providing the compounded latex composition of the present invention and prior to immersing the treated mold in the compounded latex composition according to the present invention.
The final heat-treated elastomeric film may have a tensile strength of at least about 7 MPa and an elongation at break of at least about 300 %, preferably a tensile strength of at least about 10 MPa, an elongation at break of at least about 350 %, more preferred a tensile strength of at least about 15 MPa and an elongation at break of at least about 400 % and even more preferred a tensile strength of at least about 20 MPa and an elongation at break of at least about 500 %. These mechanical properties may be measured according ASTM D 6319. A suitable range for the stress retention is 35 to 90 %, preferably 50 to 80%.
The dip-molding process of the present invention can be used for any latex article that can be produced by a dip-molding process known in the art.
The present invention further relates to an elastomeric film made from the latex composition according to the present invention or obtained by the method according to the present invention for preparing a polymer latex composition or the compounded latex composition according to the present invention.
The present invention also relates to an article comprising the elastomeric film according to the present invention. The article may be selected from health care devices formed from elastomeric films or including elastomeric films, surgical gloves, examination gloves, condoms, catheters, industrial gloves, textile-supported gloves and household gloves, preferably surgical gloves. As mentioned above, elastomeric films made from polymer latex compositions comprising the polymer latex of the present invention and an oxirane functional compound can by repaired and recycled.
Method for repairing an elastomeric film or article comprising said elastomeric film
The present invention also relates to a method for repairing an elastomeric film made from the polymer latex composition of the present invention by a) providing an elastomeric film made from the polymer latex composition of the present invention that is damaged or an article comprising such a damaged elastomeric film, the damaged elastomeric film having at least surfaces to be reconnected, b) re-joining the surfaces of the damaged film, c) heating or annealing the damaged elastomeric film while maintaining intimate contact of the rejoined surfaces of the damaged film at a temperature of 40°C to 200°C.
Items formed from an elastomeric film may be collected and sorted and optionally sterilized for handling purposes. The items where there is damage, but not to the extent that they cannot be re-used, may be separated and the surface where there is damage is optionally further cleaned. This cleansing may be by washing with hydrogen peroxide or other sterilizing fluid or by passing under a carbon dioxide air stream or UV light to make sure there are no pathogens present. In the location of damage, the surfaces of the damaged film that have separated from one another may be brought together such that they contact one another, for example if there is a hole the edges of the hole are brought into contact and the surface may be heated so that the elastomeric film can soften and the surfaces seal together to repair the damage after which the surface is allowed to cool and reveal a repaired or self-healed surface. The heating may be carried out where pressure is applied to the contacting areas of the damaged surface.
Method for recycling an elastomeric film or article comprising said elastomeric film
The present invention also relates to a method for recycling an elastomeric film made from the polymer latex composition of the present invention or an article comprising such an elastomeric film by cutting, shredding or comminuting said elastomeric film or article to form particles of the elastomer, optionally blending the obtained particles with particles of virgin elastomer, and forming a recycled film or article by subjecting the particles to a pressure of 1 - 20 MPa and a temperature of 40°C to 200°C.
Elastomeric materials such as gloves may be collected and if necessary, they can be sorted so that the nitrile containing materials are collected together while the other material is discarded or sent to alternative recycling or reprocessing facilities. The collected material can be then washed and decontaminated if necessary, much like is done for the repairi ng/self-healing process. The material can then be comminuted into particle sizes of not more than 2 mm average diameter, preferably not more than 1 mm average diameter and ideally of diameters in the range of 0.15 to 0.75 mm, more preferably 0.2 to 0.3 mm average diameter of the particle size. The comminution or grinding process may be carried out at less than room temperature or indeed under cryogenic conditions to enable facile processing and to keep the material as particles before processing further. The cool conditions avoid any re-joining of the particles until needed. The material may be stored at room temperature, such as temperatures in the range of 20 to 25 °C, or under such conditions that avoid rejoining of the particles until required. The material may be ground further before being fed to a blender where the material is blended with other materials, for example particles of virgin elastomeric material and customary processing aids and additives. If there is no blending step, the material can be fed directly to a thermal processing system where the particles/crumb is hot pressed, 2-roll milled, calendered or extruded under pressure and at heated conditions i.e., more than 40 °C to allow fluidity in the material as a result of bonds within the material being broken, e.g., the bonds within beta hydroxy esters the material and at this stage the material can also be molded into the required final shape. After this the material can be cooled, optionally in molds or as part of an extrusion process to produce an end product that is formed from recycled material.
Use of polymer latex composition
The present invention relates to use of the polymer latex composition according to the present invention or obtained by the method according to the present invention for preparing a polymer latex composition for the production of dip-molded articles or for coating or impregnating a substrate, preferably a textile or ceramic substrate.
Furthermore, the present invention relates to use of a polymer latex obtained by free-radical emulsion polymerization of a mixture of ethylen ically unsaturated monomers comprising at least 2.5 wt.-% of an ethylenically unsaturated acid, wherein the ethylenically unsaturated acid comprises an acid functional group; and a spacer group separating the ethylenically unsaturated group and the acid functional group by at least 4 atoms; for providing microbial resistance in a polymer latex composition for the preparation of an elastomeric film and/or in an elastomeric film made from the polymer latex composition. The weight percentage is based on the total weight of the ethylenically unsaturated monomers in the monomer mixture. As used herein, the term “microbial resistance” refers to the prevention of growth and/or inhibition of microorganisms, preferably microorganisms selected from the group comprising at least one strain of bacteria, at least one strain of fungi, mold, yeast, algae and mixtures thereof. According to the present invention, the use of the polymer latex composition provides microbial resistance against at least one strain of bacteria, at least one strain of fungi, mold, yeast, algae and mixtures thereof in a polymer latex composition for the preparation of an elastomeric film and/or in an elastomeric film made from the polymer latex composition.
The at least one strain of bacteria may be selected from the group consisting of gram-negative bacteria, gram-positive bacteria and mixtures thereof. Gram-positive and gram-negative bacteria are well known in the art and are described, e.g., in Biology of Microorganisms, "Brock", Madigan MT, Martinko JM, Parker J, 1997, 8th Edition. Gram-negative bacteria are characterized by two membranes (outer and inner membrane) and usually contain a high amount of lipopolysaccharide and a thin single-layer of peptidoglycan, while gram-positive bacteria contain only one membrane and usually have virtually no lipopolysaccharide, a multi-layered thick peptidoglycan and the coat contains teichoic acids. The at least one strain of bacteria may be selected from the group comprising Pseudomonas sp., such as Pseudomonas aeruginosa, Pseudomonas pseudoalcaligenes, Pseudomonas putida, Pseudomonas stutzeri, Pseudomonas mendocina, Pseudomonas oleovorans subsp. Oleovorans, Pseudomonas fluorescens, and mixtures thereof; Burkholderia sp., such as Burkholderia cepacia; Escherichia spp. such as Escherichia coli; Alcaligenes sp. such as Alcaligenes faecalis; Staphylococcus sp. such as Staphylococcus aureus; Enterococcus sp. such as Enterococcus faecalis; Bacillus sp. such as Bacillus halodurans; Salmonella sp.; Legionella; Comomonas aquatica; Brevundimonas intermedia; Rhizobium radiobacter; Spingobium yanoikuyae; Caldimonas sp.; Hydrogenophaga sp.; Alishewanella agri; Arthrobacter sp.; Chryseomicrobium amylolyticum; Microbacterium sp.; Microbacterium paraoxydans; Micrococcus luteus; Exiguobacterium aurantiacum; Klebsiella pneumoniae; Rhodococcus ruber; Proteus hauseri; Enterobacter cloacae; and mixtures thereof.
The at least one strain of fungi may be selected from the group comprising Saccharomyces cerevisiae; Pichia membranifaciens; Rhodotorula mucilaginosa; Fusarium sp. ; Aspergillus sp. such as Aspergillus niger, Aspergillus brasiliensis, and mixtures thereof; Penicillium sp. such as Penicillium pinophilum, Penicillium funiculosum, and mixtures thereof; Aureobasidium pullulans; Geotrichum sp.; Acremonium sp.; Alternaria sp.; Cladosporium sp.; Mucor sp.; Rhizopus sp.; Stachybotrys sp.; Trichoderma sp.; Dematiaceae sp.; Phoma sp.; Eurotium sp.; Scopulariopsis sp.; Aureobasidium sp.; Monilia sp.; Botrytis sp.; Stemphylium sp.; Chaetomium sp.; Mycelia sp.; Neurospora sp.; Ulocladium sp.; Paecilomyces sp.; Wallemia sp.; Curvularia sp.; Vishniacozyma sp.; Yarrowia lipolytica; Verticillium sp.; Candida albicans; Aspergillus niger; Penicillium ochrochloron; Geotrichum candidum; and mixtures thereof.
The at least one strain of yeast may be selected from the group comprising Saccharomyces cerevisiae; Pichia membranifaciens; Rhodotorula mucilaginosa; and mixtures thereof. The at least one strain of algae may be selected from the group comprising Chlorella vulgaris; Chlorella emersonii; Stichococcus bacillaris; Pleurococcus sp.; Anacystis montana; and mixtures thereof.
According to the present invention, the acid functional group of the ethylenically unsaturated acid may be selected from carboxylic acid groups and phosphorous containing acid groups. Suitable phosphorous containing acid groups may be selected from phosphoric acid groups and phosphonic acid groups. Preferably, the acid functional group of the ethylenically unsaturated acid is selected from carboxylic acid groups.
The ethylenically unsaturated acid comprising an acid functional group and a spacer group separating the ethylenically unsaturated group and the acid functional group by at least 4 atoms may be selected from compounds having the structure:
CHR2=CR1 - A - X, wherein
R1 is selected from H and Ci-C4 alkyl;
R2 is selected from H or - A - X;
A is a divalent spacer group separating the ethylenically unsaturated group and the functional group X by at least 4 atoms independently at each occurrence selected from: - (C(0) - W)n- Y - (0)m- and - (CH2)k - O - (C(O))P- Y - (O)m- wherein n, m, k and p are integers independently at each occurrence selected from 0 or 1 ; W is - O - or - NR3 -;
R3 is selected from H and Ci-C4 alkyl;
Y is selected from optionally substituted linear, branched, cyclic or aromatic C2 to C3o divalent hydrocarbon or hetero hydrocarbon groups;
X is selected from - C(O)OH and - P(O)(OH)2, preferably - C(O)OH; with the proviso that if X is - C(O)OH m is 0; or
- A - X is selected from - C(O) -O - (Y -C(O) - O)i - H, wherein I is an integer from 2 to 10, preferably from 2 to 7; and mixtures thereof. Preferably, the ethylenically unsaturated acid comprising an acid functional group and a spacer group separating the ethylenically unsaturated group and the acid functional group by at least 4 atoms is selected from carboxy (C2-C3o)alkyl (meth)acrylates, C7 to C15 fatty acids having a terminal ethylenically unsaturated group mono (meth)acryloyloxy alkyl esters of dicarboxylic esters and more preferred from carboxy (C2-Ci2)alkyl (meth)acrylates and omega-(meth)acryloyoloxy (C2-Ci2)alkyl succinates. Particularly preferred are 2- (meth)acryloyloxyethyl succinate, 2-carboxyethyl acrylate and oligomers thereof having the structure CH2=CH-C(O)-O-(C2H4-C(O)-O)I-H with I being an integer from 2 to 7 and mixtures thereof.
Suitable monomers of ethylenically unsaturated acid comprising an acid functional group and a spacer group separating the ethylenically unsaturated group and the acid functional group by at least 4 atoms are commercially available from Solvay (Belgium) as Sipomer® p-CEA, Sipomer® PAM 100, Sipomer® PAM 200, Sipomer® PAM 300, Sipomer® PAM 4000, and Sipomer® PAM 5000.
The amount of ethylenically unsaturated acid comprising an acid functional group and a spacer group separating the ethylenically unsaturated group and the acid functional group by at least 4 atoms is at least 2.5 wt.-%, preferably at least 2.8 wt.-%, even more preferably at least 3.0 wt.-%, most preferably at least 3.6 wt.-%, based on the total weight of the ethylenically unsaturated monomers in the monomer mixture. The amount of ethylenically unsaturated acid comprising an acid functional group and a spacer group separating the ethylenically unsaturated group and the acid functional group by at least 4 atoms may be up to 10.0 wt.-%, up to 9.5 wt.-%, up to 9.0 wt.-%, up to 8.5 wt.-%, up to 8.0 wt.-%, up to 7.5 wt.-%, up to 7.0 wt.-%, up to 6.5 wt.-%, up to 6.0 wt.-%, based on the total weight of the ethylenically unsaturated monomers in the monomer mixture. A person skilled in the art will appreciate that any range defined by an explicitly disclosed lower limit and an explicitly disclosed upper limit is disclosed herewith. Accordingly, the amount of ethylenically unsaturated acid comprising an acid functional group and a spacer group separating the ethylenically unsaturated group and the acid functional group by at least 4 atoms may be in a range of from 2.5 to 10.0 wt.-%, preferably from 3.0 to 10.0 wt.-%, more preferably from 3.6 to 10.0 wt.-%, even more preferably from 3.6 to 8.0 wt.-%, most preferably from 3.6 to 6.0 wt.-%, based on the total weight of the ethylenically unsaturated monomers in the monomer mixture.
Further, the present invention relates to use of at least 2.5 wt.-% of an ethylenically unsaturated acid in a mixture of ethylenically unsaturated monomers in the preparation of a polymer latex by free-radical emulsion polymerization of a mixture of ethylenically unsaturated monomers; wherein the ethylenically unsaturated acid comprises an acid functional group; and a spacer group separating the ethylenically unsaturated group and the acid functional group by at least 4 atoms; for providing microbial resistance in a polymer latex composition for the preparation of an elastomeric film and/or in an elastomeric film made from the polymer latex composition. The weight percentage is based on the total weight of the ethylenically unsaturated monomers in the monomer mixture.
The ethylenically unsaturated acid comprising an acid functional group and a spacer group separating the ethylenically unsaturated group and the acid functional group by at least 4 atoms as well as the weight percentages may be as described above.
Surprisingly, it has been found that the polymer latex composition and/or the elastomeric film made from the polymer latex composition according to the present invention is effective against microorganism and provides microbial resistance without the use of conventional biocides.
The present invention will be further illustrated with reference to the following examples.
Figures
Figure 1 : Model density charts for bacteria, yeast and fungi in dip slides.
Figure 2: Bacterial efficacy on the surface of medical examination gloves (Examples 1 a, 2a, 6a to 8a) - Log reduction from challenge inoculum.
Examples
The following abbreviations are used in the Examples:
TSC = total solid content
PS = particle size
CMIT = 5-chloro-2-methyl-2H-isothiazolin-3-one
MIT = 2-methyl-2H-isothiazolin-3-one
BIT = benzisothiazolinone
CFU = colony forming unit
MAA = methacrylic acid
Bd = butadiene
ACN = acrylonitrile
BCEA = 2-carboxyethyl acrylate oligomer (Sipomer® p-CEA) tDDM = tert-dodecyl mercaptan Na4EDTA = tetra sodium salt of ethylenediaminetetraacetic acid
ZnO = zinc oxide
ZDEC = zinc diethyldithiocarbamate
In the following all parts and percentages are based on weight unless otherwise specified.
Determination of physical parameters:
The dispersions were characterized by determination of TSC, pH value, viscosity (Brookfield LVT) and z-average particle size. Furthermore, the final films were tested for bioburden levels, challenge tests and bactericidal efficacy.
Determination of TSC:
The determination of total solids content is based on a gravimetric method. 1 - 2 g of the dispersion was weighed into a tared aluminum dish, on an Analytical balance. The dish was stored for 1 h at 120°C in a circulating air oven until constant mass was reached. After cooling to room temperature, the final weight was then re-determined. The solids content was calculated as follows:
Figure imgf000040_0001
where, minitiai = initial mass of latex, and nifinai = mass after drying.
Determination of pH value:
The pH value was determined according to DIN ISO 976. After applying a 2-point calibration using buffer solutions, the electrode of a Schott CG 840 pH meter was immersed in the dispersion at 23°C and the constant value on the display was recorded as the pH value.
Determination of viscosity:
The latex viscosity was determined at 23°C using a Brookfield LVT viscometer. Approximately 220 ml of the liquid (freed of air bubbles) was filled into a 250 ml beaker and the spindle of the viscometer was immersed up to the mark on the spindle. The viscometer was then switched-on and after approximately 1 minute the value was recorded until it was constant. The viscosity range determines the choice of spindle and rotational speed and the factor for the recorded value to calculate the viscosity. Determination of the particle size (PS):
The z-average particle size was measured using a Malvern Zetasizer Nano S (ZEN 1600) using dynamic light scattering. The latex sample was diluted with deionized water to the turbidity level described in the manual and transferred in the test cuvette. The cuvette was gently mixed to make the sample homogenous and the cuvette was placed in the measurement device. The value was recorded as software generated z-average particle size.
Dipped film preparation
Nitrile latex with compounding materials at the desired pH value was stirred for 24 h unless specified in individual examples below, at room temperature, and then coagulant dipped as follows.
A ceramic spade was washed with soap and then thoroughly rinsed with deionized water before drying in an air-circulating oven set at 65-70°C (spade temperature, 55-60°C) until dry.
A solution of coagulant was prepared by dissolving calcium nitrate (18 % wt.) and calcium carbonate (2% wt.) in deionized water.
The dry spade was then dipped into the salt solution, removed and then dried in an air-circulating oven set at 70-75°C (spade temperature, 60-65°C) until dry. The salt-coated spade was then dipped into the desired, compounded latex (which has total solid content of 18 wt.-% and matured for 24 hours at room temperature after compounding) for a dwell time of 5 seconds, before removing it and placing the latex-coated spade into an air circulating oven, set at 100°C for 1 min, to gel the film.
The thus gelled film was then washed in a tank of deionized water set to 50-60°C for 1 min, before curing in an air-circulating oven set to 120°C for 20 min; after which, the thus cured/vulcanized film was cooled, and removed from the spade before aging for 22 h in an air-circulating oven set to 100°C.
Finally, the cured films were manually stripped from the spade, a typical dried film thickness was 0.05 - 0.25 mm.
The films prepared from the latexes were tested for their bacterial efficacy. Bio-sterility determination of latex
This method gives a total count of microorganisms, and the selective detection of yeasts and molds in latex or fluids using dip slide. Prior to sample preparation, glassware must be cleaned, sterilize and dried at 70°C. The dip slide tube to screw cap to be remove and dip into the fluid for 5 sec. The dip slide can be either dipped or used by pouring the liquid to be tested onto the agar surface, in case of small sample quantities. The dip slide into the tube was removed and closes tightly. Each dip slide tubes were labeled with sample type, sample source, dilution factor (if any), test date and any other necessary information to ensure trace ability. Incubation of dip slide is to be performed at 30°C for 5 days. The level of the microorganisms, yeasts and molds was observed and recorded on the dip slide pad for the first 24 h, then the incubation was continued. After the incubation period, various results can be observed on the pad and the density of the colonies growth should be interpreted according to the model density charts.
Evaluation of the degree of contamination (density of colonies growth) on each sample by referring to model density chart as shown in Figure 1. If after 48 hours, the sample does not show the presence of microorganisms on the dip slide or the degree of contamination is < 103 CFU/ml for both total bacterial count and total yeast or mold count, then it shows no contamination issue. However, if the sample shows the contamination of microorganisms with the degree >103 CFU/ml for either total microorganisms count or total yeast or mold count or both, hence it means microbial infection occurred in the latex and biocide would be required.
Most bacteria give rise to red colonies. The bacterial count/ml of the sample is determined by comparing the density of the colonies appearing on the slide with densities shown on the model chart. Growth appearing on the slide may consist either purely of fungi or yeasts or may be caused by both fungi and yeasts forming mixed growth. Fungi give rise to soft and fluffy colonies, while yeast colonies are usually ball shaped and slightly puffed up. Sometimes they are flat and dry. Comparison of yeast growth with the model chart is carried out as with bacteria.
Quantification of Biocides in polymer dispersion and latex
Analysis was carried out according to Global Analytical Method (GAM) 11 for isothiazolinone biocides which allows for the identification and quantification of biocides (MIT/CMIT/BIT) in dispersions and lattices. 2.5 % aluminum sulphate aqueous solution is prepared in a 100 mL volumetric flask, 2.5g (± 0.01 g) of aluminum sulphate was added, dissolved in deionized water and made up to volume. For reagent preparation, a graduated cylinder to measure 450 ml of methanol was used and transferred to a 1 L glass bottle. 50 ml of the 2.5% aluminum sulphate aqueous solution was added and mixed until fully homogenized.
The test was carried out in High performance liquid chromatography (HPLC). 100 ml of acetonitrile using a graduated cylinder was measured and transferred to a 1 L glass bottle for HPLC mobile phase preparation. 900 ml of water and 50 pL of orthophosphoric acid as buffer was added and mixed until fully homogenized.
Biocide Standards Preparation
2 g (± 0.05 g) of 1 .5% CMIT/MIT solution was weighted into a 50 ml volumetric flask. 0.01 g (± 0.005 g) of BIT was added to the same volumetric flask; dissolved and filled up to the mark with the GAM 11 method reagent. This stock solution contained approximately 450 ppm of CMIT, 150 ppm of MIT (1.5% CMIT/MIT contains 3 parts of CMIT and 1 part of MIT) and approximately 194 ppm of BIT.
Sample Preparation
2 g (± 0.05 g) of the sample was weighted into a 21 mL vial and the weight was recorded (“Sample Wt”). 10 mL of GAM 11 method reagent was added and the total weight was recorded (“Final Wt”), cap was closed and vigorously shaken using the shaker for 30 min. The sample was centrifuged at 14,500rpm for 15 min to obtain a clear supernatant. The supernatant was filtered through a 0.45 pm syringe filter into a vial and analyzed by HPLC. A blank containing only the GAM 11 method reagent was measured additionally.
Analytical Instrument parameters (HPLC-DAD):
Column: Kinetex 5u C8 150 x 4.6mm
- Isocratic run
Pump A: 80:20 acetonitrile: water [as rinse solvent for shutdown method only]
- Pump B: 90:10 water: acetonitrile, 0.005% orthophosphoric acid
Flow Rate: 0.7 mL/min
- Oven Temperature: 40°C
- Wavelength: 275 nm for MIT and CMIT, 318nm for BIT
Runtime: 15 min
Injection Volume: 10 pL
Retention time: MIT - 3 min;
CMIT - 7 min
BIT - 12 min. Determination of bioburden levels of polymer samples (Sterility Testing)
The principle of this test is to access the microbial growth after incubation at an appropriate temperature and time. The growth media appropriate to the test organisms are inoculated with known aliquots of each sample. The test involved a bioburden analysis and was carried out using serial dilutions in triplicate plated out on agar plates (nutrient agar incubated at 30°C for 2 days for enumeration of bacteria and on malt extract agar incubated at 25°C for 5 days for enumeration of yeasts and molds).
Testing method:
A serial dilution of the test sample in MRD (Maximum Recovery Diluent) under aseptic conditions was prepared. The center of the plate was inoculated with 0.1 mL of the sample or serial dilution of the sample (or 0.1 g if the sample is viscous and difficult to dispense) and spread using a sterile spreader. The petri dishes were inverted and incubated in an incubator at the appropriate temperature (25°C for fungi and 30°C for bacteria). The plates were removed and inspected for growth after 48 h incubation for bacteria and 120 h incubation for fungi.
The results were recorded for any growth on the media plates and inspect for growth was counted as CFU/g or CFU/mL, taking into account the dilution factor. Total viable count per mL was calculated as total number of colonies (30-300 per plate) x 10 (to allow for 100 pL to 1 mL volume correction) x dilution factor. The differentiation of yeast and mold colonies is a matter of experience, but yeasts generally form circular, smooth colonies, whereas molds form irregular, rhizoid colonies. If in doubt, it was confirmed by microscopic identification. The used plates were sterilized using an autoclave then disposed of the inactivated plates via the normal waste disposal system.
Determination of the Challenged Test properties on latex
A biocide efficacy or challenge test is a procedure in which a product is challenged by exposure to specified types of bacteria and fungi to determine whether it is adequately preserved. Each sample was challenged with a pool of bacterial or fungal strains at high concentration.
Test organisms should be representative of those likely to occur as contaminants during use and should consist of Gram-positive and Gram-negative bacteria, moulds and yeasts. Wild type isolates obtained as a result of contamination of earlier batches of a product may also be included. The organisms were inoculated into samples of the product and aliquots removed at appropriate intervals (usually weekly) for the determination of survivors. Measured volumes of the sample were removed, and viable organisms enumerated. At weekly intervals the samples were re-challenged.
The data generated was used to determine the threshold concentration of biocide required to protect a product against microbial spoilage. The repeated inoculation study was a good simulation of the type of repeated exposure products may be subjected to during manufacturing, shipping, and use and may be used to predict the preservative’s performance under end-use conditions. Table 1 : Standard bacterial and fungal strains
Figure imgf000045_0001
Table 2: Wild type bacterial and fungal strains isolated from infected Synthomer products
Figure imgf000045_0002
Determination of the bactericidal efficacy on the surface of surface of medical examination Gloves
Standard test methods for determination of bactericidal efficacy on the surface of medical examination gloves were tested in accordance with ASTM D7907-14(2019). The methods incorporate bacterial challenges in two different formats: Method (A) a saline or buffered saline solution, and Method (B) a saline or buffered saline solution containing an organic load. Each method represents a different means of microbial contamination that can be expected in the healthcare environment. Results of the test methods described in this document are limited to bactericidal efficacy against vegetative bacteria. The tests for the current invention involved Method (A) in the main.
Challenge bacteria, should be American Type Culture Collection (ATCC) strains. To ensure vital bacteria that are not far removed from wild type characteristics, bacteria utilized in any phase of these studies should be no more than five passages from the original stock received. Challenge bacteria which used in this study were:
A) Pseudomonas aeruginosa ATCC 9027 (Gram negative bacteria)
B) Klebsiella pneumoniae ATCC 4352 (Gram negative bacteria)
C) Staphylococcus aureus ATCC 6538 (Gram positive bacteria)
D) Enterococcus faecalis ATCC 29212 (Gram positive bacteria).
Specimen A test preparation with a surface area of 1cm2 was cut from the glove. The specimen with the required surface area may be prepared by cutting a circular with a punch die.
The inoculum was prepared by inoculating an agar plate with a pure culture of the appropriate challenge organism utilizing a standard streak isolation technique. A plate was incubated at appropriate temperature for 18 to 24 h. 3-5 isolated colonies with identical colony morphology were selected, the colonies were transferred into a tube containing 5 mL of sterile saline solution. The suspension was adjusted to match a 0.5 McFarland turbidity standard.
The Challenge Delivery Option involved the following - 20pL aliquot of the prepared challenged inoculums was placed on the sterile cover slip. With the forceps, the edge of the test specimen was rested on the surface of the challenged bacteria. All the samples were evaluated at contact times: 0, 5, 10, 15, 20, 25 and 30 min. When the specified contact time was completed, the specimen was immediately removed from the cover slip with forceps and the specimen was placed into a centrifuge tube containing 10 ml of sodium thiosulphate solution (neutralizer solution) and mixed for 15 s using a vortex mixer. The number of recovered bacteria in duplicate was determined by standard plate count method. All the data was in the form of colony forming unit (CFU).
The log and percent reduction of the bacteria resu Iti ng% from the contact with the specimen is calculated using the following formula: Log reduction from challenge inoculum = Cl - TS expressed in log 10 scale (1 Ox); and % bacterial reduction efficacy from challenge inoculum ■ 100;
Figure imgf000047_0001
with Cl = Bacteria (CFU) in challenge inoculum (average between challenge inoculum titer at the beginning and the end of test session); and
TS = CFU extracted from antibacterial treated test specimen.
‘Log Reductions’ convey how effective a product is at reducing pathogens. The greater the log reduction the more effective the product is at killing bacteria and other pathogens that can cause infections.
A log reduction takes the power in the opposite direction. For example, a log reduction of
1 is equivalent to a 10-fold reduction or, to put it another way, moving down one decimal place or a 90% reduction. Hence, for every additional Log reduction number, example log reduction of 3, as illustrated above, is a 99.9% reduction compared with a log reduction of 6 which is equivalent to a 99.9999% reduction.
Example 1 : Preparation of polymer latex (Control)
2 parts by weight (based on polymer solids) of a seed latex (average particle size 36 nm) and 807 parts by weight of water (based on 100 parts by weight of monomer including the seed latex) were added to a nitrogen-purged autoclave and subsequently heated to 30°C. Then 0.01 parts by weight of Na4EDTA and 0.005 parts by weight of Bruggolite FF6 dissolved in 2 parts by weight of water were added, followed by 0.08 parts by weight of sodium persulfate dissolved in 2 parts by weight of water. Then, the monomers (35 parts by weight of ACN, 57 parts by weight of Bd, 6 parts by weight of MAA), and were added together with 0.6 parts by weight of tDDM over a period of 6 h. Over a period of 10 h 2.2 parts by weight of sodium dodecyl benzene sulfonate, 0.2 parts by weight of tetra sodium pyrophosphate and 22 parts by weight of water were added. The co-activator feed of 0.13 parts by weight of Bruggolite FF6 in 8 parts by weight of water was added over 9 h. The temperature was maintained at 30°C up to a conversion of 95 %, resulting in a total solids content of 45 %. The polymerization was short-stopped by addition of 0.08 parts by weight of a 5 % aqueous solution of diethylhydroxylamine. The pH was adjusted using potassium hydroxide (5 % aqueous solution) to pH 7.5 and the residual monomers were removed by vacuum distillation at 60° C. 0.5 parts by weight of a Wingstay L type antioxidant (60% dispersion in water) was added to the raw latex, and the pH was adjusted to 8.2 by addition of a 5 % aqueous solution of potassium hydroxide. 0.05 parts by weight of BIT and 0.04 parts by weight of formaldehyde were used as biocides for standard preservation. The following characterization results were obtained for Example 1 :
TSC = 45.0 wt. %; pH = 8.2,
Tg = -15°C,
Viscosity = 30.5mPas (1/60);
PS, Pz = 120nm.
Example 1a: Preparation of dip-coated film (Control)
A dry, salt-coated spade was dipped into the diluted compounded latex solution with 18 % TSC comprising of 0.8 phr S, 0.7 phr ZDEC, 1 phr ZnO and titanium dioxide at pH 10 with a dwell time of 5 seconds before the film was gelled at 100°C for 1 minute, washed with deionized water for 1 minute (in a tank set at 50-60 °C), followed by drying and curing/vulcanization in an air-circulating oven set at 120°C for 20 min, to ensure complete drying and crosslink formation.
Example 2: (Control without biocide)
This was an exact repeat of Example 1 but without biocide.
Example 2a: (Control without biocide)
This was an exact repeat of Example 1 but without biocide, under preparation of dip-coated film similar to Example 1 a.
Example 3: 1.2 wt.-% of BCEA
The composition was prepared in the same manner as in Example 1 except that 4.8 parts methacrylic acid was used and 1.2 part of Sipomer® p-CEA a mixture of 2-carboxyethyl acrylate oligomers commercially available as from Solvay (Belgium) was used but without biocide. The pH was adjusted to 7.1 .
Example 4: 2.4 wt.-% of BCEA
The composition was prepared in the same manner as in Example 1 except that 3.6 parts methacrylic acid was used and 2.4 part of BCEA was used but without biocide. The pH was adjusted to 7.1.
Example 5: 3.6 wt.-% of BCEA
The composition was prepared in the same manner as in Example 1 except that 2.4 parts methacrylic acid was used and 3.6 part of BCEA oligomers was used but without biocide. The pH was adjusted to 7.1 . Example 6: 6.0 wt.-% of BCEA
The composition was prepared in the same manner as in Example 1 except that no methacrylic acid was used and 6 part of BCEA was used but without biocide.
The following characterization results were obtained for Example 6:
TSC = 45.0 wt. %; pH = 7.1 ;
Tg = -22°C;
Viscosity = 22.5mPas (1/60);
Particle size, Pz = 127nm.
Example 6a: Preparation of dip-coated film (6.0 wt.-% of BCEA)
This was an Example 6, under preparation of dip-coated film similar to Example 1a.
Example 7: 6.0 wt.-% of 2-acryloyloxyethyl succinate
The composition was prepared in the same manner as in Example 1 except that no methacrylic acid was used and 6 part of 2-acryloyloxyethyl succinate was used but without biocide. The pH was adjusted to 7.1 .
Example 7a: Preparation of dip-coated film (6.0 wt.-% of 2-acryloyloxyethyl succinate)
This was an Example 7, under preparation of dip-coated film similar to Example 1a.
Example 8: 6.0 wt.-% of 2-methacryloyloxyethyl succinate
The composition was prepared in the same manner as in Example 1 except that no methacrylic acid was used and 6 part of 2-methacryloyloxyethyl succinate was used but without biocide. The pH was adjusted to 7.1 .
Example 8a: Preparation of dip-coated film (6.0 wt.-% of 2-methacryloyloxyethyl succinate)
This was an Example 8, under preparation of dip-coated film similar to Example 1a.
Bio-sterility Screening for Latex
The bio-sterility test results of Examples 1 to 8 are shown in Table 3. Table 3: Bio-sterility dip slides results
Figure imgf000050_0001
Example 1 with biocide were found to pass the bio-sterility results after 9 months. Example 2 without biocide, Example 3 with 1 .2 parts, and Example 4 with 2.4 parts of BCEA failed the bio-sterility test and infection was observed. Example 5 with 3.6 parts of BCEA, Example 6 with 6 parts of BCEA, Example 7 with 6 parts of 2-acryloyloxyethyl succinate and Example 8 with 6 parts of 2-methacryloyloxyethyl succinate, have passed the biosterility test without any contamination. Usually, latex without biocides addition will be prone to microbial infection within a month, but at 3.6 parts and above for BCEA, 2-acryloyloxyethyl succinate, and 2-methacryloyloxyethyl succinate, the efficacy of anti-microbial was observed.
Screening for Microbial Infection Example 1 -2 were found to be sterile on receipt, Example 2 was heavily infected with bacteria. This Example was disinfected by overnight incubation with 350 ppm hydrogen peroxide. All four uninoculated samples were free from infection after 6 weeks storage at room temperature.
Table 4: Residual biocide levels in the polymer samples
Figure imgf000051_0001
Example 6 is not prone to microbial infection and remains infection-free even after 6 months from production without the addition of biocides.
Biocide Efficacy Testing
The ability of polymer samples to resist microbial degradation was evaluated through a series of inoculations and re-inoculations, the results are depicted in Tables ,5 and 6. Example 2 (unpreserved control) was used as a control to test for the effectiveness of bacterial and fungal inocula used in the experiment. This sample failed all rounds of bacterial and fungal challenge, thus confirming the potencies of the inocula (Tables 5 and 6).
The sample with standard preservation (Example 1) withstood the first bacterial challenge but became infected after the second bacterial challenge (Table 5). The infection persisted following subsequent challenges and was still present 2 weeks after the last challenge. Apart from the no biocide control, all the test samples passed all four fungal challenge tests (Table 6).
Both the latex with B-CEA (Example 6), 2-acryloyloxyethyl succinate (Example 7) and 2- methacryloyloxyethyl succinate (Example 8) withstood four repeated bacterial challenges - both sets of samples were free from bacteria two weeks after the last challenge. Table 5: Bacterial growths rating 7 days after inoculation
Figure imgf000052_0001
0: No colonies found; 1 : 1 -10 colonies found; 2: 1 1 -100 colonies found; 3: more than 100 colonies found recognizable; Streaks not fully grown; 4: Streaks fully grown. Standard bacterial strains + wild type strains isolated from Synthomer production sites.
Table 6: Yeast and mould growths rating 7 days after inoculation
Figure imgf000052_0002
0: No colonies found; 1 : 1 -10 colonies found; 2: 1 1 -100 colonies found; 3: more than 100 colonies found recognizable; Streaks not fully grown; 4: Streaks fully grown. Standard fungal and yeast strains + wild type strains isolated from Synthomer production sites.
Bacterial efficacy on the surface of medical examination gloves
A total of 4 challenged bacteria were used in this study to determine the bactericidal efficacy on the surface of gloves. The results were tabulated as shown below. Table 7: Log reduction from challenge inoculum
Figure imgf000053_0001
Examples 6a to 8a show better bacterial efficacy than Example 2a (without biocide) and comparable or better bacterial efficacy than Example 1 (with biocide). Example 7a shows prominent bacterial efficacy on gram positive bacteria.
Table 8: % Bacterial reduction efficacy from challenge inoculum
Figure imgf000053_0002
Examples 6a to 8a show better % bacterial efficacy compared to Example 2a (without biocide). Example 6a shows 2x of reduction efficacy compared to Example 1 (with biocide).
Example 7a shows prominent bacterial efficacy on gram positive bacteria.

Claims

52 CLAIMS A polymer latex composition for the preparation of an elastomeric film comprising a polymer latex obtainable by free-radical emulsion polymerization of a mixture of ethylenically unsaturated monomers comprising: (a) 15 to 99 wt.-% of conjugated dienes; (b) 0 to 80 wt.-% of ethylenically unsaturated nitrile monomers; (c) 0 to 70 wt.-% of vinyl aromatic monomers; the sum of ethylenically unsaturated nitrile monomers (b) and vinyl aromatic monomers (c) being 0.95 to 84.95 wt.-%; (d) 2.5 to 10.0 wt.-% of an ethylenically unsaturated acid comprising an acid functional group, and a spacer group separating the ethylenically unsaturated group and the acid functional group by at least 4 atoms; and (e) 0 to 65 wt.-% of co-polymerizable ethylenically unsaturated compounds, wherein monomers (a) to (e) are different from each other and the weight percentages being based on the total weight of the ethylenically unsaturated monomers in the monomer mixture; and wherein the pH of the polymer latex composition is lower than 7.5. The polymer latex composition according to claim 1 , wherein the acid functional group of the ethylenically unsaturated acid (d) is selected from carboxylic acid groups and phosphorous containing acid groups, preferably carboxylic acid groups; and/or wherein the ethylenically unsaturated acid (d) is selected from compounds having the structure: CHR2=CR1 - A - X, wherein R1 is selected from H and C1-C4 alkyl; R2 is selected from H or - A - X; A is a divalent spacer group separating the ethylenically unsaturated group and the functional group X by at least 4 atoms independently at each occurrence selected from: - (C(O) - W)n - Y - (O)m -; - (C(O) - W)n - Y - O - C(O) - Y - and - (CH2)k - O - (C(O))P- Y - (O)m -; wherein n, m, k and p are integers independently at each occurrence selected from 0 or 1 ; 53 W is - O - or - NR3 -; R3 is selected from H and C1-C4 alkyl; Y is independently at each occurrence selected from optionally substituted linear, branched, cyclic or aromatic C2 to C30 divalent hydrocarbon or hetero hydrocarbon groups; X is selected from - C(O)OH and - P(O)(OH)2; with the proviso that if X is - C(O)OH m is 0; or - A - X is selected from - C(O) - O - (Y -C(O) - O)i - H, wherein I is an integer from 2 to 10, preferably from 2 to 7; and mixtures thereof, wherein (d) preferably is selected from carboxy (C2-C3o)alkyl (meth)acrylates, C7 to C15 fatty acids having a terminal ethylenically unsaturated group and mono (meth)acryloyloxy alkyl esters of dicarboxylic esters and more preferred from carboxy (C2-Ci2)alkyl (meth)acrylates and omega-(meth)acryloyloxy (C2-Ci2)alkyl succinates and most preferred from 2-(meth)acryloyloxyethyl succinate, 2- carboxyethyl acrylate and oligomers thereof having the structure CH2=CH-C(O)- O-(C2H4-C(O) — O)I— H with I being an integer from 2 to 7 and mixtures thereof. The polymer latex composition according to any of the preceding claims, wherein the ethylenically unsaturated acid (d) is present from 3.0 to 8.5 wt.-%, preferably from 3.4 to 8.0 wt.-%, more preferably from 3.6 to 7.0 wt.-%, even more preferably 3.6 to 6.5 wt.-%, most preferably 3.6 to 6.0 wt.-%, based on the total weight of the ethylenically unsaturated monomers in the monomer mixture; and/or further comprising (f) up to 10.0 wt.-%, preferably in a range of from 0 to 7.0 wt.-%, more preferably in a range of 0 to 3.5 wt.-% of an ethylenically unsaturated acid being different from (d) based on the total weight of the ethylenically unsaturated monomers in the monomer mixture; and/or wherein the ethylenically unsaturated acid (d) and the ethylenically unsaturated acid (f) is present in an amount the range of up to 10.0 wt.-%, preferably in the range of up to 8.0 wt.-%, more preferably in a range of up to 6.0 wt.-%, based on the total weight of the ethylenically unsaturated monomers in the monomer mixture, wherein the ethylenically unsaturated acid (f) preferably is selected from ethylenically unsaturated carboxylic acids and salts thereof preferably selected from (meth)acrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, and salts thereof, ethylenically unsaturated polycarboxylic acid anhydride, preferably selected from maleic anhydride, methacrylic anhydride, cis-cyclohexene-1 ,2- 54 dicarboxylic anhydride, and dimethylmaleic anhydride, bromomaleic anhydride, 2,3-dichloromaleic anhydride, citraconic anhydride, crotonic anhydride, itaconic anhydride, (2-dodecen-1-yl) succinic anhydride; polycarboxylic acid partial ester monomers and salts thereof, preferably selected from monomethyl maleate, monomethyl fumarate, monoethyl maleate, monoethyl fumarate, monopropyl maleate, monopropyl fumarate, monobutyl maleate, monobutyl fumarate, mono(2-ethyl hexyl) maleate, mono(2-ethyl hexyl) fumarate and combinations thereof; The polymer latex composition according to any of the preceding claims wherein (a) the conjugated dienes are selected from butadiene, isoprene, 2,3-dimethyl- 1 ,3-butadiene, 2-ethyl-1 ,3-butadiene, 1 ,3-pentadiene, myrcene, ocimene, farnasene and combinations thereof, (b) the ethylenically unsaturated nitrile monomers are selected from (meth)acrylonitrile, alpha-cyanoethyl acrylonitrile, fumaronitrile, alphachloronitrile and combinations thereof; (c) the vinyl aromatic monomers are selected from styrene, alpha-methyl styrene, vinyl toluene and combinations thereof; and (e) the co-polymerizable ethylenically unsaturated compounds are selected from
(e1 ) alkyl esters of ethylenically unsaturated acids, preferably selected from methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, iso-propyl (meth)acylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate and combinations thereof;
(e2) hydroxyalkyl esters of ethylenically unsaturated acids, preferably selected from 2-hydroxy ethyl(meth)acrylate;
(e3) amides of ethylenically unsaturated acids, preferably selected from (meth)acryl amide, N-methylol amide groups and combinations thereof;
(e4) vinyl carboxylates, preferably vinyl acetate;
(e5) alkoxyalkyl esters of ethylenically unsaturated acids, preferably selected from ethoxyethyl acrylate, methoxyethyl acrylate and combinations thereof,
(e6) monomers having at least two ethylenically unsaturated groups, preferably selected from divinyl benzene, ethylene glycol 55 dimethacrylate, 1 ,4 butanediol di(meth)acrylate and combinations thereof;
(e7) ethylenically unsaturated silanes; and combinations thereof. The polymer latex composition according to any of the preceding claims, wherein the mixture of ethylenically unsaturated monomers for the polymer latex comprises:
(a) 20 to 98 wt.-% of conjugated dienes, preferably selected from butadiene, isoprene and combinations, thereof, more preferred butadiene;
(b) 1 to 60 wt.-% of ethylenically unsaturated nitrile monomers, preferably acrylonitrile;
(c) 0 to 40 wt.-% of vinyl aromatic monomers, preferably styrene;
(d) 3.0 to 10.0 wt.-% of ethylenically unsaturated acids comprising an acid functional group, and a spacer group separating the ethylenically unsaturated group and the acid functional group by at least 4 atoms, preferably selected from 2-(meth)acryloyloxyethyl succinate, 2-carboxyethyl acrylate and oligomers thereof having the structure CH2=CH-C(O)-O- (C2H4-C(O) -O)I-H with I being an integer from 2 to 7;
(e1 ) 0 to 25 wt.-% of Ci to C8 alkyl (meth)acrylates;
(e3) 0 to 10 wt.-% of amides of ethylenically unsaturated acids;
(e4) 0 to 10 wt.-% of vinyl esters;
(e7) 0 to 10 wt.-% of ethylenically unsaturated silanes;
(f) 0 to 10.0 wt.-% of ethylenically unsaturated acids different from (d); the weight percentages being based on the total weight of the ethylenically unsaturated monomers in the monomer mixture. The polymer latex composition according to any of the preceding claims being completely free of a biocide; and/or wherein in the pH of the polymer latex composition is in the range of 6.0 to less than 7.5, preferably of 6.5 to 7.2; and/or further comprising an oxirane functional compound. A method for preparing a polymer latex composition comprising: preparing a polymer latex by free-radical emulsion polymerization of a mixture of ethylenically unsaturated monomers comprising:
(a) 15 to 99 wt.-% of conjugated dienes;
(b) 0 to 80 wt.-% of ethylenically unsaturated nitrile monomers;
(c) 0 to 70 wt.-% of vinyl aromatic monomers; the sum of ethylenically unsaturated nitrile monomers (b) and vinyl aromatic monomers (c) being 0.95 to 84.95 wt.-%
(d) 2.5 to 10.0 wt.-% of an ethylenically unsaturated acid comprising an acid functional group; and a spacer group separating the ethylenically unsaturated group and the acid functional group by at least 4 atoms;
(e) 0 to 65 wt.-% of co-polymerizable ethylenically unsaturated compounds; and
(f) 0 to 10.0 wt.-%, of an ethylenically unsaturated acid being different from (d); wherein monomers (a) to (f) are different from each other and the weight percentages being based on the total weight of the ethylenically unsaturated monomers in the monomer mixture; and adjusting the pH of the polymer latex composition to be lower than 7.5. Use of the polymer latex composition according to any of claims 1 to 6 or obtained by the method according to claim 7 for the production of dip-molded articles or for coating or impregnating a substrate, preferably a textile or ceramic substrate. A compounded latex composition suitable for the production of dip-molded articles comprising the polymer latex composition according to any of claims 1 to 6 or obtained by the method according to claim 7, and optionally adjuvants selected from sulfur vulcanization agents, accelerators for sulfur vulcanization, crosslinkers, polyvalent cations and combinations thereof, wherein the monomer mixture preferably further comprises an ethylenically unsaturated acid (f). A method for making dip-molded articles by a) providing a compounded latex composition according to claim 9; b) immersing a mold having the desired shape of the final article in a coagulant bath comprising a solution of a metal salt; c) removing the mold from the coagulant bath and optionally drying the mold; d) immersing the mold as treated in step b) and c) in the compounded latex composition of step a); e) coagulating a latex film on the surface of the mold; f) removing the latex-coated mold from the compounded latex composition and optionally immersing the latex-coated mold in a water bath; g) optionally drying the latex-coated mold; h) heat treating the latex-coated mold obtained from step e) or f) at a temperature of 40°C to 180°C, preferably 70°C to 120°C; and i) removing the latex article from the mold, wherein after step a) and prior to step d) the compounded latex composition preferably is matured for at least 3 hrs, preferably from 24 to 48hrs. An elastomeric film made from the latex composition according to any of claims 1 to 6 or obtained by the method according to claims 7 or the compounded latex composition according to claim 9. An article comprising the elastomeric film according to claim 1 1 , preferably being selected from surgical gloves, examination gloves, condoms, catheters, industrial gloves, textile-supported gloves and household gloves, preferably surgical gloves. A method for repairing an elastomeric film according to claim 11 or an article according to claim 12 a) providing elastomeric film according to claim 11 that is damaged or an article according to claim 12 comprising a damaged elastomeric film, the damaged elastomeric film having at least surfaces to be reconnected, b) re-joining the surfaces of the damaged film, c) heating or annealing the damaged elastomeric film while maintaining intimate contact of the rejoined surfaces of the damaged film at a temperature of 40°C to 200°C. A method for recycling an elastomeric film according to claim 11 or an article according to claim 12 comprising an elastomeric film by cutting, shredding or comminuting said elastomeric film or article to form particles of the elastomer, optionally blending the obtained particles with particles of virgin elastomer, and forming a recycled film or article by subjecting the particles to a pressure of 1 - 20 MPa and a temperature of 40°C to 200°C. Use of a polymer latex obtained by free-radical emulsion polymerization of a mixture of ethylenically unsaturated monomers comprising: at least 2.5 wt.% of an ethylenically unsaturated acid, the weight percentage being based on the total weight of the ethylenically unsaturated monomers in the monomer mixture, 58 wherein the ethylenically unsaturated acid comprises an acid functional group; and a spacer group separating the ethylenically unsaturated group and the acid functional group by at least 4 atoms; for providing microbial resistance in the polymer latex composition for the preparation of an elastomeric film and/or in an elastomeric film made from the polymer latex composition, wherein the ethylenically unsaturated acid preferably is selected from 2- (meth)acryloyloxyethyl succinate, 2-carboxyethyl acrylate and oligomers thereof having the structure CH2=CH-C(O)-O-(C2H4-C(O) -O)i-H with I being an integer from 2 to 7 and mixtures thereof, more preferably from 2-carboxyethyl acrylate and oligomers thereof having the structure CH2=CH-C(O)-O-(C2H4-C(O) -O)i-H with I being an integer from 2 to 7. Use of at least 2.5 wt.% of an ethylenically unsaturated acid in a mixture of ethylenically unsaturated monomers in the preparation of a polymer latex by free- radical emulsion polymerization of a mixture of ethylenically unsaturated monomers; the weight percentage being based on the total weight of the ethylenically unsaturated monomers in the monomer mixture, wherein the ethylenically unsaturated acid comprises an acid functional group; and a spacer group separating the ethylenically unsaturated group and the acid functional group by at least 4 atoms; for providing microbial resistance in the polymer latex composition for the preparation of an elastomeric film and/or in an elastomeric film made from the polymer latex composition, wherein the ethylenically unsaturated acid preferably is selected from 2- (meth)acryloyloxyethyl succinate, 2-carboxyethyl acrylate and oligomers thereof having the structure CH2=CH-C(O)-O-(C2H4-C(O) -O)i-H with I being an integer from 2 to 7 and mixtures thereof, more preferably from 2-carboxyethyl acrylate and oligomers thereof having the structure CH2=CH-C(O)-O-(C2H4-C(O) -O)i-H with I being an integer from 2 to 7.
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